How can u do it with out wifi

You can't, not with anything less than an iPhone 12 which would let you use 5G.

Click on a link below for full instructions about how to update with wi-fi or 5G (see: Use 5G with your iPhone

https://support.apple.com/HT211828), or using a computer if you have storage or connectivity issues.

Update your iPhone, iPad, or iPod touch. Click here --> https://support.apple.com/HT204204

Or this video:

"How to update your iPhone or iPad" click here --> https://youtu.be/csJAEyvvruY

Thanks