Members
Members are customers who have joined your loyalty program. Typically, a customer becomes a Member by creating an online account on your store. For Shopify merchants, how a customer becomes a Member depends on the type of customer accounts your store uses:- With legacy customer accounts, customers become Members by creating an account with an email and password.
- With customer accounts, customers become Members when they sign in using their email and the one-time 6-digit verification code sent to them and access Smile while signed in.

Guests
On Shopify, Guests are customers who have not yet become a Member using one of the methods described above.On BigCommerce only customers who have created store accounts are sent to Smile - no “Guest” customers are sent. BigCommerce stores will only have Member and Excluded customers identified in Smile. If you would like a customer to be synced over to Smile, be sure to get them to create an account on your store.