How can I do a back up if I don’t have wifi? I only have my cell phone plan.??

I am being prompted to back up my Iphone 12. It’s been about 2 weeks since it was last done. That was also the day I got rid of home wifi to save money. The directions tell me I need wifi to back it up. I am concerned that my information

won’t be safe if I use a free wifi spot in town tk do my back. Any helpful suggestions?