Move photos from pictures to a collection in an album?

• Open the Photos App
• Tap Library
• Find the photo(s) and tap Select in the upper right hand corner
• Tap the photo and you'll see a check mark in it
• Tap the square box with an up arrow
• Tap Add to Album
• Find the Album from the list and tap it and the photo will be moved there

If you long press on a picture, you get a menu with "Add to Album." Is this what you need?

Or do you mean something else? I may be confused, because collections aren't in albums. The "albums" collection can be included in the Pinned Collections section. And with Collection>Modify,

you can add any album to Collections -- it's at the bottom of the menu.

Let us know if this works for you…