Though Apple’s iOS updates are not suppose to delete any user information from the device, exceptions arise. To bypass this threat of losing information, and to quell any anxiety that may accompany that fear, back up your iPhone before doing an update.
Does updating to iOS 13 delete anything?
iOS 13 will download and install, your phone will be unusable while it chugs, and it’ll then restart with the brand-new experience ready for you to try out.
Will updating iOS 14 delete everything?
In addition to making the process a little easier when you want to update the OS, it also will keep you from losing all your favorite photos and other files if your phone is lost or destroyed. To see when your phone was last backed up to iCloud, go to Settings > your Apple ID > iCloud > iCloud Backup.