Social Login for your community
Overview
Enabling social login allows members to log in using their existing accounts from available social media platforms, like Google, Facebook, and LinkedIn instead of creating a new username and password.
Who can enable social login?
Only the community hosts can enable social login in your community.
How to enable social login
Go to Settings.
Click Social Login under Single Sign-On.
Click Configure on the right-side of the app you want to configure. 
Before proceeding, you must create an app on the respective social platform,
For LinkedIn,
In the page, create an app.
Copy the Client ID and Primary Client Secret from the Auth tab.
Getting back to the community, paste the Client ID → Application ID and Application Secret → Primary Client Secret.
Once done, click Save.