MetaMask is a software cryptocurrency wallet used to interact with the Ethereum blockchain. It allows users to access their Ethereum wallet through a browser extension or mobile app, which can then be used to interact with decentralized applications. Once the MetaMask wallet is created, the user is given a 12-word Seed Phrase / Secret Recovery Phrase. MetaMask never keeps user personal/private data on servers. Everything is encrypted in the browser and MetaMask is protected by the user's own password.