App for customer sign in

[wturner1]

Hello,

I am currently in the process of moving my site to Shopify and would like recommendations for an app to handle forms which manage customer sign in, account sign up, and password resetting. I would want the forms to make API call to Shopify to create a Shopify account, inform my LMS of any changes and update current systems not in Shopify, and verify information like passwords with my own digital database.