The edit button has been moved - it is now below the photo, when you view it enlarged.
See:Use Apple Intelligence in Photos on iPhone - Apple Support
Remove distractions from your photos

You can use the Clean Up tool to remove distracting objects in the background of a photo.
Note: Clean Up is available in iOS 18.1 on all iPhone 16 models, iPhone 15 Pro, and iPhone 15 Pro Max in most regions around the world.
- Go to the Photos app
on your iPhone. - Open a photo, tap
, then tap Clean Up. - Note: After you tap Clean Up, some items may be highlighted automatically so you can quickly tap to remove them.
- Tap, brush, or circle what you want to remove.
- Use two fingers to pinch to zoom or pan the image.
- Note: If you brush over a person’s face, the face may become blurred with a pixelated effect.
- When you’re finished, tap Done.