How can I put my photos in alphabetical order?

I don't believe that is possible. See the 'Manage your albums' section in:

Organize and find your photos on your iPhone, iPad, or iPod touch - Apple Support

"With iOS 14, you can also sort the photos within your albums. Here's how:

1. Go to an album, then tap the More button .
2. Tap Sort, then choose a sorting option, like Custom Order, Oldest to Newest, or Newest to Oldest."