Wallet

You need a crypto-currency wallet if you want to transact (transfer or receive) with your crypto-currency.

A wallet usually stores your public and private key information. The Public key of a receiver is used to encrypt an intended message, which can only be unlocked using the corresponding Private key.

Among popular wallets for Bitcoin transactions is BitcoinCore, which can be downloaded from Bitcoin.org. For Ethereum, you can use Ethereum wallet and similarly for litecoin you can use litecoin wallet.

A word of caution: If you loose your private key, there is no way you can access your funds again. It is advisable to keep a back-up in an encrypted form, so that you can protect yourself against theft or loss of your device which has your current wallet.