As you can see in the screenshot below, there is a user with only JIRA Software in the Application list.

The user has access to the Service Desk too.
So, I am trying to understand:
Where can I configure this? and
Why does she only see JIRA Software while other users have both JIRA Software and Service Desk. What jira-thingy is determining that? Is it the group membership of the user?
We are running JIRA Software v7.8 and Service Desk v3.11
Many thanks in advance,
Dimitris