How does the feature "system extionsions" run

[Alenlin]

I just want to configure something and find system extionsions that I can't understand. Also there is no relative document to explain it.

 

[YiannisH_3CX]

Hello @Alenlin

System extensions is a group of extensions used by the system to perform various tasks. Some of them are configured out of the box and cannot be changed like the voicemail extension for example and others are created by the users like digital receptionists queues and ring groups.
Can you tell us what you are trying to configure so we can try and help?