An address is used to receive bitcoin and is represented as a string of letters and numbers. If you wish to send bitcoin to someone, they must send you one of their addresses.
A Bitcoin wallet allows users to generate as many addresses as they require. Wallets also allow users to send bitcoin to a provided address. When bitcoin is sent to an address, only the owner of the private key(s) which derived that address is capable of spending the bitcoin.
On a technical level, an address is usually a hash of a public key. In this case, it will begin with a ‘1’. Less frequently, an address is a hash of a script, in which case it will begin with a ‘3’.