You can send USDC to an external wallet directly from the app. In the Withdraw flow, choose Crypto wallet, select the network the receiving wallet supports, and paste the deposit address from that wallet.
To send any other token or coin to an external wallet, you need to export your private key. Go to Settings, then Account, then Export. You have two keys: Solana and EVM (Base, BNB Chain, Monad, and Ethereum). Copy the one that matches the network the token is on. Import it into a compatible wallet. You are not creating a new wallet. You are accessing the same wallet through a different app.
Your private key is full access to your wallet. Never share it with anyone, never paste it into a website, and never store it anywhere digitally. If someone gets your key, they have access to everything in it.