MetaMask lets you manage Ethereum wallets and access dApps securely from your browser or mobile device. To log in, install the official MetaMask extension or mobile app, open it, and enter your password if you already have a wallet. If you are creating a new wallet, follow the setup flow, create a strong password, and securely back up your recovery phrase — this phrase is the only way to restore access. When connecting to a website, MetaMask will show a connection request; verify the domain and requested permissions before approving. Never share your private key or recovery phrase with anyone, and be cautious of phishing sites and unsolicited links. Enable biometric unlock on mobile and keep your software up to date. For added safety, consider using a hardware wallet for large balances and review transaction details carefully (recipient address, network, and gas fees) before confirming. If you suspect your seed phrase is compromised, move funds to a new wallet immediately. MetaMask provides network switching to access different chains, but always confirm you are using the intended network to avoid sending tokens to incompatible addresses. By combining cautious habits with MetaMask’s access controls, users can interact with web3 applications confidently and safely.