How can I download all my photos/videos from icloud to iphone device and reduce icloud size?

ayush71 wrote:

I would like to reduce icloud size. My Iphone has enough space to download all the photos/videos from icloud to the device. How can I download all the photos/videos from icloud with deleteing from icloud and having the original copy on the iphone device.

You can’t. That’s not how it works. You can download all the photos and keep them on your phone only but you would have to delete them from iCloud in order to free up space in iCloud.

This explains how to archive data in iCloud.

Archive or make copies of the information you store in iCloud - Apple Support