If you know them, choose your users from the available list or else click Show Advanced to create a filter. Users can be filtered according to full name, surname, first name, email address, city/town, country, confirmed, first access, last access, last login, username, authentication. If you have set a custom profile field, this is available too from the "Profile" dropdown box Select users from the list.
If what you want to do can actually be done, most likely it will be by using the Advanced options.
I unfortunately don't have a Moodle installation in front of me at the moment, but do you see a Show advanced button in the New filter section for the Bulk user actions page? I believe it should be there, the same as when you're choosing to Browse list of users which also has the New filter section.
In the Advanced filter you have many more fields to try to search through your users. I think you'd want to look at either the Profile or Course role fields to try to narrow down by department.
Please let us know if this is what you were talking about, and if you had any further questions please let us know!
I see all the new filter action but in it
it does not see department wise filter in bulk action.