How to go to iCloud and delete file ?
How to go to iCloud and delete files
If you had enabled iCloud Photos and then if you delete Photos and Videos / Notes / Voice Memos / Videos / Reminders from the iCloud it is deleted from iPhone too, and vice-versa.
And if you happen to take a backup either over iTunes or iCloud after deleting Photos and Videos all the photos are deleted from the backup (iCloud/iTunes) too.