How can members update their payment information?

There are two ways for your members to update their payment information. 

The first is to login to their membership dashboard and click the "Update Payment Information" link. 

A modal will pop up to confirm, and once they do, they'll be sent an email directly from your Shopify store to update their payment information.

The email that is sent can be modified by going to your Shopify dashboard and clicking Settings > Notifications, and selecting the "Customer Payment Update Request" email.

The second way to do it is to go to your Shopify Customer and scroll down to the "Payment method" box on the right side. When you click "More actions", you will have the option to send a link to the customer so they can update their own card (this sends the same email as above), or you can manually enter credit card details on behalf of the customer by clicking the "Replace card" button.