This question already has an answer here:
Logged in user is a system admin. When I try to post on chatter tab using @communityUser I am not getting user suggestion. Cant we access Community user @mention?
I tried to find an answer here - (Unable to @mention Partner user on chatter feed by Salesforce Internal User)
First of all, The answer to above question is related to record post/feed. But i am not posting feed on any record to make it view with the Community base URL. I am trying to post from Chatter tab.
Secondly, the answer suggests the visibility of the Chatter post from the internal user must be set to Everyone. The default is internal
users. - I didn't find any way mentioned in the answer to achieve
this(how to set this visibility?)
Please suggest if I am missing some customization setting to do