A wallet address is the destination of a crypto transfer: a string of 26–62 characters derived from your public key. Knowing an address lets someone send you money but not spend it — spending requires the private key, which cannot be derived from the address.
Three things to know about an address
An address is network specific. The same coin uses a different address on different networks.
USDT on the TRC-20 network usually starts with T, on
ERC-20 with 0x. Money sent on the wrong network technically arrives, but the
recipient cannot reach it.
BEP-20 and ERC-20 addresses look identical. Both start with 0x and are the
same length. The format does not tell you the network — only the page you copied the address from
does.
A memo or destination tag is part of the address. Some networks and some exchanges have an extra field alongside the address. Without it the money reaches the exchange's pooled account but not your account.
How to avoid a mistake
Always copy, never type. After pasting, compare the first and last four characters against the source — malware that swaps addresses on the clipboard is widespread and that check is the only protection against it. For a larger sum or a new address, send a small test transfer first.