Technology at home
Plan a phone-storage cleanup
Check what is using space before choosing what to remove. If you use iCloud Photos, deleting a photo can delete it from your other synced devices too. A cleanup plan needs to account for that.
A text to start with
My iPhone has 2 GB free out of 64 GB. Photos and downloaded podcasts may be taking most of it. I use iCloud Photos. Help me inspect the storage categories and compare options for freeing local space without losing photos. Explain syncing versus a separate backup, link to Apple's current instructions, and leave every deletion for me to review.
Example request. Change the details to fit your situation.What to check in the answer
Apple says deletions in iCloud Photos sync across devices. Seeing a photo on another synced device does not make that device an independent backup. Check Apple's instructions for Optimize Storage if you want smaller local copies. Before removing anything you intend to keep, create a separate copy and open a few files to confirm it worked.
What to do next
Open the phone's storage breakdown and start with a category you understand, such as downloaded podcast episodes you can obtain again. Review items individually. For photos, choose a storage setting or a separate export based on Apple's documentation before deleting. Stop at any instruction whose effect on your other devices is unclear.