Add comments or notes to photos

Yep. When you have selected an image, you can swipe up on it and Add a Caption. This also makes the photo searchable via what you enter.

The only thing you see when browsing is Date and location.

For everything else, including reading or adding caption, slide it up or tap the (i) for info, as advised earlier.

Metadata stores a lot of that information. You could use a metadata editor to add more information.

This way the information would stay with the picture if you want to share a photo with someone.