Click on the Contacts page on the left side of the screen.
Click the Archived tab.
Use the search bar at the top of the list to search for a specific Contact.
Click on the Contact you want to reactivate.
Navigate to the Details Tab, and click the Reactivate Contact button in the upper-right corner.
Click the ellipses (three dots) in the upper-right-hand corner of the screen.
Click Send Invite.
Once the Contact is reactivated, it is best practice to associate it with its related Account.