History database with changing old and new values

What version? For 8.x.x we had the history manager, that no longer exists for version 9.x

The time trace database when entered in Designer allows the Manager tool to view the history when enabled for each object. That is for the columns that are set to log changes.

This can be enabled by clicking on "View" in the top menu in Manager and then selecting TimeTrace. Then if you click on an employee for example, down in the bottom window it will say TimeTrace and you have to enable the icon with the clock symbol. 

I appreciate your help. I have one more question: what is the function of a history database?

To move historical data off of the main database. If that is not done the main database can increase dramatically in size and cause performance issues for the nightly maintenance jobs such as the reindex job.