MetaMask Wallet Extension is one of the most popular self-custodial Web3 wallets, designed to provide seamless access to decentralized applications, digital assets, and blockchain networks directly from a web browser. Built primarily for the Ethereum ecosystem, MetaMask allows users to store, send, receive, and swap cryptocurrencies such as ETH and ERC-20 tokens while also supporting multiple EVM-compatible networks like Polygon and BNB Chain.