How to buy/sell coins on CEX? What is the transaction process like?

To buy or sell cryptocurrency on a centralized exchange (CEX), you need to complete these 6 core steps:

1. 

   Pick a regulated CEX and create an account (using your email or phone number).

2. Complete identity verification (KYC) by uploading your ID and passing a liveness check.

3. Set up security tools, strongly recommended Google Authenticator.

4. Deposit funds (buy USDT with fiat currency, or transfer crypto from another wallet).

5. Place a buy or sell order (choose between a market order or a limit order, then confirm the trade).

6. Check your holdings or withdraw your funds.

If you're just starting out, begin with a small amount of money. Get familiar with the interface using the watchlist or a tiny test trade before you scale up.

Now let's break down each step in detail, starting from the absolute basics.

II. What Is a Centralized Exchange (CEX)?

A centralized exchange (CEX) is an online platform run by a private company, specifically designed for buying, selling, and trading cryptocurrencies. All trade orders, custody of assets, and user data are managed and maintained by this single "central" entity.

The easiest way to understand a CEX is to picture a blend between a traditional bank and a stock exchange:

• Like a bank: You open an account, submit your ID for KYC verification, and deposit your money into the platform’s unified system. The balance you see on the exchange is essentially a ledger entry in the platform's database, not an asset directly controlled by a private key on a blockchain.

• Like a stock exchange: The exchange runs a central order book system that automatically matches buyers and sellers. The matching engine works in milliseconds, making the whole process smooth, efficient, and fast.

This centralized architecture allows a CEX to deliver a user experience similar to traditional finance, dramatically lowering the entry barrier for regular people. Today, over 90% of global crypto trading volume still happens on centralized exchanges.

III. The Full Trading Process, Step-by-Step

Step 1: Choose an Exchange and Register an Account

(1) How to pick a trustworthy exchange?

Not all exchanges are created equal. Here's what a beginner should look at:

• Compliance and Regulation: Prioritize platforms licensed in major jurisdictions, such as Binance, Coinbase, and Kraken. Avoid obscure, unregulated platforms.

• Security Track Record: Research whether the platform has suffered major security breaches and whether it publishes a "Proof of Reserves" audit, demonstrating that it holds customer funds 1:1.

• Fee Transparency: Understand spot trading fees, contract trading fees, withdrawal fees, and any hidden costs. For high-frequency trading, the gulf between a 0.1% fee and a 0.2% fee can mean dozens of percentage points in cost difference per year.

• Liquidity: Platforms with the highest trading volume deliver the fastest execution and the best prices. For example, Binance accounts for roughly 42% of global crypto volume, with daily BTC/USDT volume often reaching tens of billions of dollars.

(2) How to register an account

Using Binance as an example:

• Go to the official website or app and click "Register." Enter your email address or phone number.

• Create a login password. The system will send a verification code; enter it to complete registration.

• The platform will immediately prompt you to bind your phone number, Google Authenticator, and other security measures, setting a solid security habit from day one.

Security reminder: Always double-check that you are on the official website. For instance, Binance's official domain is binance.com. Never click on links from unverified sources.

Step 2: Complete Identity Verification (KYC)

KYC, which stands for "Know Your Customer," is a legal requirement for any legitimate exchange. Its purpose is to comply with anti-money laundering (AML) regulations, protecting both the platform and its user base.

KYC usually comes in two tiers:

• Basic Verification: You'll fill in your legal name, nationality, and date of birth, then upload a photo of your ID card, driver's license, or passport. This is followed by a facial recognition scan and a liveness check. Some regions may also require a proof-of-address document.

• Advanced Verification: This builds on the basic tier and unlocks all features, including fiat currency on/off ramps and higher withdrawal limits.

Verification is often approved within minutes, though it can sometimes take a few hours. Think of KYC as a critical layer of fund protection. If your account gets hacked, you forget your password, or you lose your device, your KYC documentation is the only way to recover your assets. A platform with zero KYC requirements actually carries far greater risk.

Step 3: Set Up Security Verification Tools

Before you deposit a single cent, lock down your account security. Beginners often overlook this step, but it’s the most critical one.

We recommend implementing these four security measures:

Google Authenticator works on a time-based algorithm, generating a fresh 6-digit numerical code every 30 seconds even when your phone is offline. It effectively blocks SIM swap attacks and SMS interception risks.

How to set it up:

1. Download Google Authenticator from your phone's app store.

2. Go to your exchange’s security settings and choose "Two-Factor Authentication."

3. Use the Google Authenticator app to scan the QR code displayed on the screen.
   4- Crucial step: You absolutely must write down the backup key (Secret Key) that the system shows you. Store it in a safe, offline place. You’ll need it to restore access if you ever get a new phone.

Step 4: Deposit Funds

This is where "real-world money" turns into tradeable assets on-chain. There are three common ways to fund your account:

Method 1: Peer-to-Peer (P2P) Trading to Buy USDT (Most Common)

This is the most popular method for users in regions with restricted banking access. Go to the "Fiat Trading" or "P2P" section. Select USDT, then filter for verified merchants with over 1,000 completed trades and a 98-99% positive feedback rating. You pay the seller directly via bank transfer, Alipay, or similar methods. Once the seller confirms they’ve received your payment, the USDT is instantly released into your exchange account. The exchange holds the crypto in escrow, guaranteeing the safety of your money during the trade, and P2P trades typically have zero transaction fees.

Method 2: Credit/Debit Card Purchase (Fastest)

Best for a quick, small first purchase. The operation is extremely simple, but fees are on the high side, generally ranging from 2.5% to 3.99%. Go to the "Buy Crypto" or "Quick Trade" section, enter your fiat amount, select the crypto you want, link your card, and complete the one-click purchase.

Method 3: Bank Wire / ACH Transfer (Cheapest)

Ideal for larger sums. The fees are the lowest you'll find, but deposit times are longer, typically 1 to 3 business days. For example, on Bybit: after logging in, go to "Buy Crypto" > "Fiat Deposit," select USD as the currency, choose your payment method, and follow the instructions to complete the transfer.

Note: Regardless of the method, the name on your bank account must exactly match the verified name on your exchange account. A mismatch will cause the deposit to fail or trigger lengthy refund delays.

Once the deposit hits, you'll see a balance of USDT in your spot wallet. You're now ready to trade.

Step 5: Buying Cryptocurrency

Now that you have USDT, buying a target cryptocurrency involves two core actions: choosing a trading pair and selecting an order type.

(1) Selecting a Trading Pair

In the trading area, search for pairs like BTC/USDT or ETH/USDT. BTC/USDT means you are using USDT (a stablecoin pegged to the dollar) to buy Bitcoin. This is the most mainstream type of trading pair, offering the deepest liquidity and best pricing.

(2) Choosing an Order Type — Market vs. Limit

Understanding the difference between these two order types is crucial for new traders:

Market Order: This order executes instantly at the best currently available price. Speed is the priority, not price precision. It’s perfect for "I want to buy now and don’t want to wait" scenarios. The downside: during extreme volatility, the actual fill price could slip from the quote you saw when clicking the button.

Limit Order: You specify the exact price at which you are willing to buy or sell. The order only fills if the market price reaches your target. For example, if Bitcoin is at $0.93 and you think $0.89 is a better entry point, you'd set a limit buy order at $0.89. If the price never drops to that level, your order won’t go through.

The best advice for a beginner: For your very first trade, use a market order with a tiny amount of money. Get a feel for the full process quickly. Once you're comfortable, learn to use limit orders to manage cost and risk.

(3) Placing a Buy Order

• Open the trading interface and search for your trading pair (e.g., BTC/USDT).

• Choose "Market" or "Limit" order.

• Enter the amount in USDT you want to spend, or the quantity of crypto you want to buy.

• Double-check the fee and order details.

• Click "Buy." The trade is done.

Within seconds, the Bitcoin will show up in your Spot Account asset list.

Step 6: Selling Cryptocurrency

Selling follows a perfectly symmetrical logic to buying:

• Choose the same trading pair (e.g., BTC/USDT).

• Select a Market Sell (sells instantly at the current market price) or a Limit Sell (sets a target sell price and waits).

• Enter the amount you want to sell and confirm the fee.

• Click "Sell" to complete the trade.

After the sale, your funds will return as USDT in your account. From here, you have three choices:

• Keep Trading: Use the USDT to buy other cryptocurrencies.

• Cash Out: Go to the P2P market and sell your USDT back into fiat currency, withdrawing it to your bank account.

• Withdraw to a Self-Custody Wallet: Transfer your crypto to a personal hardware wallet (like a Ledger) or a non-custodial on-chain wallet. This is a good habit to build. Leaving assets on an exchange long-term carries risk. Transferring them out to a wallet where you control the private keys means you retain full ownership.

IV. Data Comparison of Major Exchanges

The following table is compiled from publicly available data as of 2026, giving you a clear, side-by-side reference:

Sources: Aggregated from multiple public fee comparison sources.

A few takeaways:

• On fees: Binance starts at a base fee of 0.10%, with an extra 25% discount if you use BNB to pay transaction fees. OKX has a marginally lower entry point at 0.08% and supports OKB discounts. Coinbase has the highest basic fees (around 0.4%–0.6%), but it offers a unique advantage in the US with its top-tier regulatory compliance and FDIC insurance on USD balances.

• On security: Coinbase and Kraken score highest on security and compliance. Both regularly release audited Proof of Reserves reports, and Coinbase carries commercial crime insurance for crypto held in its hot wallets.

• On beginner experience: Coinbase's interface is extremely clean, making it almost frictionless for a newcomer. OKX offers strong language support and a UI that's very friendly for Asian markets.

V. Frequently Asked Questions (FAQ)

Q1: Why do people buy USDT first and then use it to buy Bitcoin, instead of buying Bitcoin directly with dollars?

Three main reasons:

1. USDT is a stablecoin pegged to the dollar, so it’s widely available on fiat gateways and its price is generally stable.

2. During the time it takes to buy Bitcoin directly, the price can swing wildly, causing slippage. Locking in a USDT balance first lets you dodge that immediate volatility.

3. On major exchanges, the USDT/BTC trading pair has the deepest order books and the tightest bid-ask spread, making the actual overall cost cheaper.

Q2: Should I use a market order or a limit order as a beginner?

Use a market order for your very first trade. It guarantees you get a fill and eliminates the headache of a hanging limit order that never executes. Once you're familiar with the full flow, learn how to use limit orders to control your costs. Neither order type is strictly better; it all depends on the situation.

Q3: Why is KYC absolutely required? Will a legitimate exchange leak my info?

KYC is mandated by anti-money laundering laws. Reputable platforms store your data with high-grade encryption and stick to strict privacy policies. A platform without any KYC is actually a much bigger red flag — if you get hacked, there’s no legitimate way to reclaim your lost funds.

Q4: What’s my security setup priority right after registration?

Your non-negotiable checklist:

1. Bind Google Authenticator — it stops a hacker who has your password from logging in.

2. Set an Anti-Phishing Code — this lets you instantly spot a scam email.
   These two steps take under five minutes and will stop over 99% of common threats.

Q5: Why hasn't my deposit shown up yet?

Common causes: You selected a different blockchain network on the sending and receiving ends (always confirm both are on the exact same network before hitting send); the transaction hasn't received enough on-chain confirmations yet (Bitcoin typically needs 6); or your deposit is flagged in a routine risk screening. First, check the transaction's status on-chain using a block explorer. If it shows as confirmed, then contact the exchange’s official support.

Q6: Should I just leave my crypto on the exchange after buying it?

Not recommended for long-term holding. Even the biggest CEX platforms can theoretically be hacked. A safer habit is to transfer the bulk of your crypto off the exchange to a self-custody hardware wallet (like a Ledger) right after buying. Keep only what you plan to actively trade on the exchange.

Q7: How can I avoid getting my bank account frozen when using P2P?

Filter sellers carefully: stick to those with over 1,000 completed trades, a 99%+ positive feedback score, and a platform "Verified Merchant" badge. Avoid large transactions with brand-new merchants who have a thin trading history. Additionally, use a secondary bank account for P2P payments rather than your primary salary account to minimize the chance of an account freeze triggered by a counterparty's transaction.

Q8: How are trading fees actually calculated? What would it cost to buy $1,000 worth of Bitcoin with USDT?

Using Binance's base fee of 0.10%: a $1,000 BTC buy costs a fee of $1,000 × 0.10% = $1.00. If you hold BNB and toggle on "Pay fees with BNB," you get a 25% discount, dropping the actual cost to roughly 0.075%, or $0.75. In contrast, the same $1,000 purchase on Coinbase's entry-level model could incur a fee of $15 to $40, highlighting a significant disparity.

VI. Conclusion

Buying and selling crypto on a centralized exchange boils down to six key actions: pick a platform, register and verify, set up security, deposit funds, place a trade, and sell/withdraw. It might look like a lot of steps at first, but they follow a clear, logical flow — from establishing your identity, to moving money in, to trading assets, and cashing out.

For a beginner, four guiding principles are worth tattooing on your brain:

First, safety above all. Before you wire a single dollar onto the platform, set up Google Authenticator, create your anti-phishing code, and configure your fund password. This takes only a few minutes but will stop the vast majority of account takeover attempts dead in their tracks.

Second, go slow and start small. Use pocket change for your first attempt. Place a tiny market order and experience the complete cycle of buying and selling. Only after you’ve successfully navigated the full loop should you think about committing more capital. Don’t let FOMO drive you to dump a huge sum in during a price spike. Keep a calm, rational rhythm.

Third, pick the right tool for the job. The fee gap between exchanges is genuinely massive. A base rate of 0.10% versus 0.40% can translate to over a dozen percentage points of cost difference over a year for an active trader. Spending a little time understanding the fee structure before you sign up is a highly profitable investment in the long run.

Fourth, manage your assets like an adult. Don’t leave all your crypto sitting on an exchange indefinitely. Transfer the portion you intend to hold long-term into a self-custody wallet like a hardware wallet. Leave only the stack you need for active trading on the exchange. This is the hallmark of a responsible investor who truly understands self-sovereignty.

The world of crypto can feel information-dense, but the operational barriers keep getting lower. I hope this guide helps you take a solid first step forward.