Photos in heif are optimized. Jpeg images are larger, TIFF and RAW files are huge. Live photos are 6 seconds of motion and sound so they are big. But video takes even more space. Video projects with audio and soundtracks are ... beyond the pale... as in overflowing.
Time to check your on-board storage for iPhone - where you will make video clips, iPad - where you will edit iMovie projects, and iCloud where the photos and your devices Backups are stored.
I am at the edge of 200GB in iCloud storage but both devices have plenty of on-board space.
- Settings > General > iPhone Storage
- Settings > General > iPad Storage
- Settings > Apple ID > iCloud > iCloud+ > look at GB items for hints of where to archive off-device if needed
iCloud storage is a monthly subscription - if you want to increase your storage temporarily (maybe when going on a trip) you can go to the next level for the 4 weeks and then manage your photos, files, etc when you get back home. Then drop back to a lower storage subscription, 200GB is $3/ month, 2TB is $10/month.
Remember that apps, books, podcasts, music that you purchase on-device can be deleted and redownloaded at no cost.
