The checkout hands you a long string of letters and numbers and asks you to send money to it. That is a reasonable moment to want an explanation, so here is one.
It is a destination, not an account
An address is closer to an account number than to a password. Sharing it does nothing dangerous: it lets someone send funds in, never take funds out. The address on your order page is safe to paste anywhere, screenshot, or email to yourself.
It belongs to your order alone
We generate a fresh one for every order rather than reusing a single wallet. That is why you do not have to include a reference or a note with your payment. Money arriving at that address can only be your money, so the system knows which order to credit without you telling it.
It also means an address from an old order is dead. Always take the one from the page in front of you.
Why it looks different every time
Each blockchain formats addresses its own way. Bitcoin addresses often start bc1, Ethereum addresses start 0x and are forty two characters, Tron addresses start with a T. If the shape of what you are pasting looks nothing like what your wallet expects, that is usually a sign the network is set wrong somewhere.
The memo, when there is one
Seven networks work differently. On XRP, Stellar, Cosmos, Algorand, EOS, Hedera and TON, one address serves many accounts and a memo or tag tells the receiver which is yours. Where one is needed, our page shows it directly under the address with a warning above, because a deposit sent to those chains without the memo is usually unrecoverable.
If you do not see a memo field, your coin does not use one and there is nothing missing.
The two hour window
The address stays valid for two hours from when the order is created. That is not a sales countdown, it is how long the exchange rate behind your quote is held. Miss it and nothing is owed, nothing was taken, and a new order gives you a fresh address at the current rate.