From your private key, your wallet computes a public key, and from the public key, an address. This only works in one direction: nobody can go back from an address to the private key.
The address is what you share
An address is like an account number that you can give to anyone. Modern addresses start with bc1 and look like this: bc1q followed by a long string of letters and numbers. Older ones start with 1 or 3.
- Private key: secret, never shared, signs payments
- Public key: derived from it, used to check signatures
- Address: derived from the public key, shared to receive
A new address each time
Your wallet can create as many addresses as you want, all controlled by the same secret. Good wallets give you a fresh one for every payment you receive, so that nobody can easily link all your payments together.