Add to Album

Method 1

1. Select photos.
2. Tap add to button at the center of the bottom toolbar.
3. Choose an album type and pick an album in an album picker.
   Or tap an album in a recently used album list.

Method 2

Settings > Viewer > Assigned Album Titles should be on.

1. Open a viewer.
2. Tap Add To or album title button on the top right of the viewer.
3. Choose an album type and pick an album in an album picker.
   Or tap an album in a recently used album list.

Method 3

1. Open a viewer
2. Tap actions button on the bottom toolbar.
   (If you are using iOS 14 or earlier, tap share button instead.)
3. Tap Add to Album
4. Choose an album type and pick an album in an album picker.
   Or tap an album in a recently used album list.

Method 4

1. Open a viewer
2. Tap album titles (or "Add To" button) on the top right of the viewer.
3. Tap Show Album Bar
4. Tap an album on the album bar to assign a photo into that album.