To withdraw USDC to a centralized exchange on the mobile app, tap the three dots next to your Cash balance, select Withdraw, then Crypto wallet. On the web app, Withdraw in your cash balance menu opens it directly. Enter the amount and tap Continue.
Before sending, go to your exchange and find the USDC deposit address for one of the networks fomo lists for you (Solana, Base, BNB Chain, Monad, Ethereum, Robinhood Chain or Arc; the network list in the app shows which ones are available to you).
On Robinhood Chain you receive USDG rather than USDC, so only choose it if your exchange accepts USDG on Robinhood Chain. Only choose Arc if your exchange accepts USDC deposits on Arc.
Make sure you copy the deposit address for the correct network.
Back in fomo, the network picker starts on Solana, so select the same network first (the network button on the mobile app, the dropdown on the web app), then paste the deposit address from your exchange. Tap Review, then slide to confirm on the mobile app, or tick the warning and tap Confirm withdraw on the web app.
The network you select in fomo must match the network of the deposit address on your exchange. If your exchange gives you a Base USDC deposit address, select Base in fomo. If they give you a Solana address, select Solana. Sending on the wrong network can result in lost funds.