To enable payment gateways for accepting customer payments: Navigate to Invoices > Settings Scroll to the Payment Gateways section at the bottom Check the checkbox next to the gateways you want to enable (Stripe, PayPal, or both) Click Save Settings New gateway menus appear under Invoices > Gateways > [Gateway Name] After enabling a gateway, configure its credentials and settings: Navigate to Invoices > Gateways > [Gateway Name] Enter your API credentials (publishable key, secret key, etc.) Configure gateway-specific settings (currency, webhook settings, etc.) Enable Test Mode first to verify with sandbox credentials Test the payment flow with test payment information When ready, disable Test Mode to enable live payment processing Click Save Settings to apply changes