The field is called “Register Time”. Here is the information from the standard help:
Register Time Field
The General Ledger Setup Table
Here you can specify whether the program will register the user’s time usage. Place a check mark in the field if you want the program to register time for each user.
The program can use the User Time Register table to register how much time an individual user spends on the companies. When there is a check mark in the Register Time field, the program automatically enters information (about the user ID, date and number of minutes worked) in the User Time Register table each time the user leaves the program. The time is registered in whole minutes, so periods can be rounded up or down by as much as 30 seconds.
If you have specified a different setting in the User Setup table then the setup in the User Setup table will overrule this general setting.
You can review the information about your users in NAV 3.70 at: General Ledger - Setup - Users - User Time Registers