Settings > Menu and Function Keys > Restricted Menu Selection

Restricted Menu Selection
You can adapt the function menu to your own needs. If you want to only use some of the functions available, you can hide the remaining functions in order to shorten the menu selection. Hiding applies only to the function menu. If the functions in question are also available over a different path, for example, via the key definition menu or an already defined key, this remains available.
 
Proceed as follows:
Using the telephone (menu settings > user settings > menu definition)

COMfortel 1200 - Firmware V2.2 - COMfortel Set V3.16 - Advanced Information V07 02/2019