After you install MetaMask (be sure to install the web browser plugin), the app will create a default account for you and give you the ETH address for your default account. You will use this ETH address to receive all your different tokens in your MetaMask account.
REMEMBER: You only have one ETH address per account, and you use the same ETH address on all the different EVM-compatible networks you connect to (e.g. Ethereum Mainnet or zkSync Era).
Just click or tap on the address under your account to copy it to your clipboard. ETH addresses always begin with 0x.
You can now paste and use your MetaMask ETH address anywhere you like!