I can't find the personal hotspot on my iPhone 13 pro max

How to set up a Personal Hotspot on your iPhone or iPad - Apple Support

This assumes that your carrier (phone company) supports the feature.

Share your internet connection from iPhone - Apple Support (IE)

"Note: If Cellular Data is turned on in Settings > Cellular, but you don’t see Set Up Personal Hotspot as an option, contact your carrier about adding Personal Hotspot to your plan."

The Personal Hotspot option is a feature that may or may not be provided by your carrier. Not all carriers provide this option and some that do charge extra for the service on top of your regular monthly cell phone bill.

Tap Settings

Tap Cellular

If you do not see a Personal Hotspot option, either your carrier does not offer this feature, or it is feature that is not included with your current service.

Contact your carrier for more information