How do I free up space for iOS update on my iPhone SE?

A few updates back the IOS update offered to make temporary space for the update to occur and then "put things back". Never saw that again. Lately I'd been making room manually. I thought that having an iCloud subscription and room to spare there, the option I had seen would automatically appear. No chance. Plus, suggestions to make room are false promises, as it were, because they show how much space the DATA takes but only offers to offload the app, which frees much less space. How do I easily make room for an update to occur in a way that doesn't feel I'm doing all the work? TIA

[Re-Titled by Moderator]

Original Title: space for IOS update