To implement social sign-on for customers to register and log in to a portal built on Salesforce Experience Cloud using their Facebook or LinkedIn credentials, the identity architect should take three steps:

Create authentication providers for both Facebook and LinkedIn. Authentication providers are configurations that enable users to authenticatewith an external identity provider and access Salesforce resources. Salesforce provides predefined authentication providers for some common identity providers, such as Facebook and LinkedIn, which can be easily configured with minimal customization.

Check“Facebook” and “LinkedIn” under Login Page Setup. Login Page Setup is a setting that allows administrators to customize the login page for Experience Cloud sites. By checking “Facebook” and “LinkedIn”, the identity architect can enable social sign-on buttons for these identity providers on the login page.

Update the default registration handlers to create and update users. Registration handlers are classes that implement the Auth.RegistrationHandler interface and define how to create or update users in Salesforce based on the information from the external identity provider. The identity architect can update the default registration handlers to link the user’s social identity with their Salesforce identity and prevent duplicate accounts. References: Authentication Providers, Social Sign-On with Authentication Providers, Login Page Setup, Create a Custom Registration Handler