How to I back up to iCloud using mobile data
How do I back up files to my iCloud using mobile data not Wi-Fi
Question marked as
Top-ranking reply
That is only possible with recent iPhone models with some carriers. See the following from Back up iPhone - Apple Support
Note: On models that support 5G, your carrier may give you the option to back up iPhone using your cellular network. Go to Settings > [your name] > iCloud > iCloud Backup, then turn on or off Backup Over Cellular.