To send Ethereum from Coinbase to MetaMask, first, log in to your MetaMask wallet and copy your wallet address by clicking the “Receive” or account button. Then, access your Coinbase account, click “Send/Receive,” and select Ethereum as the cryptocurrency to send. Paste the MetaMask wallet address into the recipient field, carefully verifying its accuracy. Input the amount of Ethereum to transfer and review the transaction details, including the network fees. Once satisfied, confirm the transaction.