Photos

To the best of my knowledge, Photos does not have this facility. Instead it's part of the user environment provided by the OS. Photos is pretty unconcerned about your file name. Instead you can use keywords, albums, descriptions....

As you've been told that feature is party of the Finder/System, not Photos. To batch change the title of a number of photos to some text plus a sequential number try this user offered AppleScript: Batch Change Title to Text w/Padded Sequential Numbers.

The script compiled as an application can be downloaded from this tutorial site:  P01 - Applescripts from Photos’ User Tips Compiled as Applications (#02).

I put the app in the Dock and select the images I want to change. I then launch the script/app from the Dock.

Ok, I watched the video. This isn't a Photos thing. This is an Operating System thing.

I was able to replicate the actions in the video

Worked like a charm. This is modifying photos in a folder. I have not considered what happens if that folder is inside the Photos Library. You're on your own with that one. I'm not about tomess up my Photos Library

Are you sure it is wise to modify the filenames simultaneously? They would end up with the same filename, which might have interesting implications later on

Titles etc can all be modified in oe go by selecting all the photographs you wish to modify, then using Command and I and typing the changes you wish to see