how to sort photos in alphabetical order on macbook pro

Create a Smart Album with this criteria:

That will include every file in the library.

Now you'll be able to sort it Alphabetically A ➙ Z by Title.

In the photos app?

In the main library, you can't. That is always by date.

Add the photos to an album, then right click the album you are in, in the left hand sidebar, and choose "sort by title"