Audit logs within a contact allow you to keep track of any changes made to that specific contact details.
To view any contact audit logs, open the edit contact window and then scroll to the right to click on Audit Logs tab.
You will be viewing all contact changes in the last 7 days by default, but you can further filter by (1) type of changes, (2) user who made the changes and (3) time period when changes were made. Click on (4) Search button to view the audit logs results.