If you scroll down in the settings, you will be able to find a section for Other settings.
Here you can Enable debug log.
Also, you can enable the automatic saving of customers’ payment details.
Go to the Card settings panel and enable the option Save Cards to store customers’ card details in your website (tokenized).
Your customers will be able to make a second purchase and choose among any of the cards they’ve used before or add a new one from the checkout page.
Save PayPal details
Do the same for PayPal, and enable the option Save Payment Details to store your customers’ PayPal account details in your website (tokenized). They will be able to use the same PayPal account(s) they used for previous purchases.
Add, remove or select default payment method
If you want to give them the option to add or remove one or more cards or PayPal account from their account or set one of those as a default payment method, they can do that from My Account > Payment methods.