Tap the wallet icon at the top of the screen and choose "Deposit". The app shows your personal deposit address with a QR code — send USDC on the Polygon network to it from your own wallet. There is no amount to enter: whatever you transfer is what gets credited.

The balance is credited automatically once the transfer is confirmed on the network — usually within a few minutes. Only send USDC on Polygon: funds sent as another asset or on another network cannot be recovered.