When creating a Telegram group, the group Admin has the option to hide the list of group members, so only the Admin can see it. Telegram group members will not be able to see this list. This will keep the privacy and security of Telegram group members from spam messages and being bothered by others. Below are instructions for hiding Telegram group members.
Instructions for hiding Telegram group members
Step 1:
At the Telegram group interface, users Click on the Telegram group that you are managing and want to hide group members. Then, at the Telegram group interface, click on the group name above. Switch to the member interface of the Telegram group, click next pen icon to display customizations for this group.


Step 2:
Switch to the interface to customize information for the Telegram group. Here you scroll down and click Members section to view the list of group members and adjust Telegram group member display mode.
Step 3:
Displays a list of members of the Telegram group. Here you need Activate Hide Members mode to hide the list of group members.
Note that this feature only applies to Telegram groups with a minimum of 100 members, so you need to pay attention.