GoAffPro provides you with the option to allow affiliates, who are also customers to access their affiliate accounts from the Shopify accounts page of the store.
To allow affiliates to access their affiliate accounts from the Shopify accounts page of the store, go to the Advanced section of the Settings tab in the GoAffPro admin panel.
Here, go to the Single Sign-On section.
Now, copy the code from the box.
After this, add the code in the customer/accounts.liquid template theme file.
You also the option to choose what happens if the customer does not have an affiliate account.