How to delete photos from iCloud to free up storage?

See this https://support.apple.com/en-in/HT205856

The device is signed in with apple id and password , and photo box is turned as on https://support.apple.com/en-in/HT204264

When you delete photos from the device , the same photos will be deleted from iCloud server ( acts like a mirror ) .

Are you using iCloud Photos? Do you want to delete the photos from iCloud Photos, but keep them on the iPhone? Or do you want to delete them both from the iPhone and iCloud?

Do have saved the photos to a computer or are the photos in iCloud your only copies?

If you are using iCloud Photos on your iPhone and delete the photos from the iPhone, the photos will be deleted from iCloud as well. To free your cloud storage immediately, empty the "Recently Deleted" album in Photos. Then the photos will be deleted immediately and permanently. You should save photos, taht are important to you on a computer, before you delete them from the iPhone.