If you are the Super administrator of the Formitize account, or have the administration permissions required, you can go to Users > User Logs. This will come up with a searchable list of actions that have been taken within the Formitize account, so that you can search through them to see who may have changed or accessed something in the Formitize account.

You can filter the search by date range in order to shorten the list, and can search by inputting information related to whatever may have been changed into the search bar (Submitted form ID, Job number, etc).