A Bitcoin wallet stores the information of one’s Bitcoin, such as the Bitcoin address (like bank account numbers), and the private key to the Bitcoin address (like a pin code for an ATM card). The core function of a Bitcoin wallet is to protect users’ private keys. If one loses his wallet, those bitcoins will be gone forever.
Bitcoin wallets come in numerous forms such as PC or smartphone wallets, web wallets, paper wallets (writing down private keys in a notebook) or brain wallets (memorizing it). Each user can choose his right wallet based on his needs.