Personal Hotspot is not working on my iPhone

What is happening when you're trying to connect to your personal hotspot?

Please see this

Try connecting to Personal Hotspot again after each step.

1. Check that Personal Hotspot is turned on in Settings > Personal Hotspot. If you can't find or turn on Personal Hotspot, check that your wireless carrier enabled it and that your wireless plan supports it.
2. Restart the iPhone or iPad that provides Personal Hotspot and the other device that needs to connect to Personal Hotspot. 
3. Make sure that you have the latest version of iOS or iPadOS.
4. On the iPhone or iPad that provides Personal Hotspot, go to Settings > General > Transfer or Reset [Device] > Reset, then tap Reset Network Settings. This also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you've used before.

Use the following steps for more help with Personal Hotspot over Wi-Fi or USB.

See this link for further reference

https://support.apple.com/en-us/119837

Hotspot is a carrier provided feature. Contact your carrier if Hotspot isn't working.