A cryptocurrency wallet is a device, application or service that allows the personal storage and retrieval of digital assets. The assets or cryptocurrencies are not really stored into the wallet, but reside on the blockchain. The wallet contains the private and public keys and the addresses necessary to track these assets as well as software capable of providing a balance of what is available.
The first wallet was introduced in 2009 by Satoshi Nakamoto when he released the Bitcoin protocol for the first time.
Modern wallets can contain information regarding multiple cryptocurrencies and digital assets. They divide into soft wallets, that are kept on the cloud, and hard wallets, that are secure device which can be stored in a safe.