iPhone: Personal Hotspot Feature Missing
The iPhone's “Personal Hotspot” feature should appear in the main Settings app, just below Airplane Mode and Wi-Fi. If it is missing, it may be due to some network settings in the device which are invalid or corrupt. To resolve:
When the iPhone has restarted, go back to Settings. If Personal Hotspot does not appear on the main screen:
After this the Personal Hotspot feature should work, and should appear in the main Settings app.