To receive Bitcoin, you will first need to own a wallet and have your private keys securely written down and safely stored.
This could be a mobile wallet on your phone, a hardware wallet or a multisig wallet.
To receive a Bitcoin payment, you will need to provide whoever is sending you the Bitcoin with the public key of your wallet. This is also sometimes called the address of your wallet. To find your public key, select the "Receive" feature of whichever Bitcoin wallet you are using. This will show you your public key, it is a long string of characters, often starting with the characters bc1. The address may also be shown as a QR code. Copy this string of characters and send it to whoever is sending you the Bitcoin, so that they know where to send the Bitcoin. Alternatively, show them the QR code and they will scan it with their mobile device.
Generally, once the sender initiated the sending process from his side, your wallet will notify you of the pending transaction. Once the transaction containing the Bitcoin sent to you has been confirmed more than 6 times, you can assume that the Bitcoin is reliably in your custody.