If you have an iPhone X as shown in the footer, that model is supported with iOS 16. Currently, that is iOS 16.0.2.
If you don't have an iPhone X here, which iPhone do you have, and which iOS version?
To update a phone that won't update otherwise, use a computer. Mac and Windows can be used.
That update process is described in this article:
Update your iPhone or iPad - Apple Support
If things are badly corrupted, you can back up, factory reset, and restore (this describes reset, with links to backup and restore):
Restore your iPhone, iPad, or iPod to factory settings - Apple Support
Once you're running something more current, issues with iCloud or such can be checked, if the problems persist.