Renaming files on a smartphone is done via the Files or My Files app (Android) or Files app (iOS). Simply open the app, locate the file, long-press it, tap the menu (three dots or “Rename”), and enter the new name. On most systems, it is crucial not to change the file extension (e.g., .jpg, .pdf) to keep it usable. YouTube +3 How to Rename Files on Android How to Rename Files on iPhone/iOS Important Tips