To withdraw funds you will need a Bitcoin Lightning wallet that lets you receive Bitcoin over the Lightning Network. You can also use CashApp, Strike and other money apps.
Open Fountain and go to your Wallet. Press the three-dot menu and choose Withdraw Funds. Choose the amount you wish to deposit to generate an invoice address. Copy the invoice address then open your Bitcoin Lightning Wallet to complete the transaction. Once it has been processed, your Fountain balance will be updated and the withdrawal payment will appear in the Transactions tab.
To protect against bots from exploiting the earnings feature, new users must unlock the withdrawal option. If you haven't unlocked withdrawals yet, keep using the app as normal until this becomes available to you.