Hi Photoqueries23,
Thanks for posting in Apple Support Communities.
It sounds like you have questions about missing photos and storage. You can't increase storage on iPhone. You can clear content from iPhone to make more storage available.
You can purchase additonal iCloud storage. When using iCloud Photo library, your photos are stored on iPhone and synced to iCloud and to your other devices that have the feature enabled with the same Apple ID.
For you missing photos, check that you aren't in a specific album that may not include all the photos you're searching for. Check your Recently Deleted, and any Shared Albums that may have had the photos.
If you're missing photos or videos in the Photos app - Apple Support
Regards.