Most screens in the system will track who created the record, and when, as well as who last updated the record, and when. Hovering over either will show more information, including the time the change was made.
The application tracks any adds, edits or deletes of data to all security tables. The data is logged in the TRACE table and records the user that made the change, when the change was made as well as details of the changes made. Select fields that contain sensitive data will only show that there was a change made but not the new and old values.
User reporting can be used to audit the data by creating a User Report Type and selecting Trace as the base table. This will allow you to identify what records were changed, by whom, when and the details of the change.
Note - Trace is only available as a system report.