A cryptocurrency wallet stores the public and private keys which can be used to receive or spend a cryptocurrency. A wallet can contain multiple public and private key pairs. As a matter of fact, your cryptocurrency doesn’t store in your wallet, but in the blockchain widely distributed in the web.
Public keys, just like your bank account numbers, can be made public so anyone can deposit cryptocurrency to your accounts. Private keys, like your bank account passwords, should be kept secret as it would enable anyone possessing the keys to spend or withdraw the cryptocurrency in the account.