Hello 98SH,
You can find steps to manage your storage, photos and videos specifically, here: Manage your photo and video storage - Apple Support
We also recommend reviewing the following page. It outlines how to remove photos from your device and how this action can effect both your local and iCloud storage if you're using iCloud Photos: Delete photos on your iPhone or iPad - Apple Support
"Delete photos permanently
- Open Photos and tap the Albums tab.
- Tap the Recently Deleted album.
- In iOS 16, iPadOS 16.1, or later, use Face ID or Touch ID to unlock your Recently Deleted album.
- Tap Select.
- Select the photo or video that you want and tap Delete. If you want to delete all the photos and videos in the album, tap Delete All.
- Tap Delete Photo to confirm."
Take care!