The easiest way would be through PayPal or Square. Although, I don’t think you can sell them for cash through those platforms. Edit: they only use Bitcoin.

Coinbase is also an easy way. They can store it for you through their wallet or you can download a wallet to your computer and send it there. This is hot storage. You can buy a dedicated wallet as well. Kind of like a usb drive for offline “cold” storage. You would then send your crypto to your wallet.

There may be others.

cold = more secure but more difficult to transact
hot = less secure but easier to transact.