Metamask® Wallet:

MetaMask acts as a wallet, meaning it keeps your digital assets safe and helps you manage transactions on the blockchain. It's like having a specialized pocket in your browser where you can securely..

MetaMask also lets the user create and manage their own identities (via private keys, local client wallet and hardware wallets like Trezor™), so when a Dapp wants to perform a transaction and write to the blockchain, the user gets a secure interface to review the transaction, before approving or rejecting it.