A Bitcoin wallet is a software program in which Bitcoins are stored. Technically, Bitcoins are not stored anywhere. For every individual who has a balance in a Bitcoin wallet, there is a private key (secret number) corresponding to the Bitcoin address of that wallet. Bitcoin wallets facilitate the sending and receiving of Bitcoins and give ownership of the Bitcoin balance to the user. The Bitcoin wallet comes in many forms. The four main types are desktop, mobile, web, and hardware.