My name is***** am sorry to hear that you are having this issue.
I will be glad to assist you with this.
Do you have hotspot enabled on your iPhone?
After you set up Personal Hotspot, you can go to Settings > Personal Hotspot to turn it on or off and change your password.
If you don't see the option for Personal Hotspot, ask your carrier if you can use Personal Hotspot with your plan.
Did that work? Let me know if it doesn't and we can try another solution.