Remove photos from iPhone

If they are on iCloud because you synced them using iCloud Photos, I would create a copy of those pictures from iCloud to a computer:--> Archive or make copies of the information you store in iCloud - Apple Support

When done, all your photos are safely stored, so you can delete the ones you don't need anylonger on your iPhone (and your iCloud).

Regards

Giulio

You can't do that. iCloud is not a archive. It is a backup and if you store photos in the cloud, when you delete them from your phone, they will delete from iCloud.

If you want to keep you photos somewhere not in iCloud, you can use a true archive service like Google Photos, DropBox, Amazon Photos or even connect your iPhone to your home computer and transfer photos to your computer's photo file.