Offload or delete an app?
What each one keeps.

Offload App, Delete App and Offload Unused Apps

Offload App frees the storage the app itself uses and keeps its documents and data. Delete App removes the app and its related data. Offload Unused Apps is the automatic version of the first: when storage is low, iOS offloads apps you have not been using.

How to offload an app, or delete it

1. Open Settings › General › iPhone Storage and wait for the list of apps to load.
2. Tap an app. The screen shows the size of the app and the size of its Documents & Data.
3. Tap Offload App to keep the data, or Delete App to remove the app and its data.
4. Confirm.

You can also delete from the Home Screen: touch and hold the app, tap Remove App, tap Delete App, then tap Delete. Remove from Home Screen only moves the app to App Library and frees nothing.

Offload Unused Apps: let iOS choose

Turn it on in Settings › Apps › App Store › Offload Unused Apps. iPhone Storage may also offer it as a recommendation with an Enable button. When storage is low, iOS removes unused apps and keeps their data; each icon stays in place with a cloud symbol.

Which one frees more space

Compare the two numbers on the app's screen. If the app itself is the large part, offloading gets most of the space back. If Documents & Data is the large part, offloading frees little, because that data stays.

How to get an offloaded app back

Offloaded: tap its icon and it downloads again with its data in place. Deleted: find it in the App Store and download it again, as long as it is still available there, then sign in or restore its data from wherever it was synced.

If apps are not the big part

On most iPhones, photos and videos use more space than any app. Clearing them means you can keep the apps you use.