Stripe
Setup a account at https://www.stripe.com. You can start right away with test payments, but to start accepting live payments you need to complete the verification process.
The only needed configuration for accepting payments trough Stripe in UFPayments is to fill in your api key and client key in the Payments dashboard. You will find a test api key in your Stripe account, when you are ready to go live with payments, you can fill in your live api key.
Prefill customer email
If you collect the email of the user in the form. You have the option to prefill the user email in Stripe. This way the user does not need to fill his email address twice.
To prefill the customer email, create a text field in Umbraco Forms and set the alias to "customerEmail". The workflow checks if this field exists and passes the email address to Stripe.