With the Facebook Login option, you can provide your customers with a secure, fast, and convenient way to log into your website without them having to create a password.
To get started, visit https://developers.facebook.com/, enter or create your account and click My Apps:
Click Create App:
Select an app type and click Next:
Add display name and contact email → Click Create app:
In the Products → Add products to your app section, find Facebook Login and click the Set up button:
To select the platform for your app, click Web:
Go to Products → Settings in the left sidebar and add your website URL: yoursitename.com/userlogin/?social-login=facebook in the Valid OAuth redirect URIs field and click Save Changes (you may leave all other fields blank).
Add your App domains:
Go to your top panel and make your website public by changing your app status. Use the toggle switch.
Paste App ID and App Secret in your WP admin area: AliDropship → Settings → Accounts → Facebook Authorization.