Stripe FAQ - How to Connect a Stripe Customer account to a WordPress Account?

1. To connect the Stripe Customer to a WordPress account, go to https://dashboard.stripe.com/test/customers

2. When you create a Stripe Customer account, the email address should match the user's email address created on the WordPress site. If janedoe@ultimatemember.com is registered on your WordPress site, you should add her email address in the Customers >  Add Customer > Account email.

Note: Ultimate Member - Stripe extension automatically generates a Stripe customer account when subscribing to a plan/price or viewing the external Stripe Customer Billing page

Note: When a WordPress account is already linked to a Stripe Customer, it won't be linked to the new Stripe Customer with the same account email when you create in the Stripe.com Customer form. You can change the Stripe Customer that is linked to the WordPress account by editing the profile in WP Admin > Users > Edit a Profile > see "Stripe Customers".