To set up a personal hotspot on your iPhone or iPad (Wi-Fi + Cellular), go to Settings > Personal Hotspot and toggle it on (if you don't see Personal Hotspot in Settings, tap Cellular > Personal Hotspot). Make note of the Wi-Fi password.
Open the Wi-Fi menu on the device you need to connect to the internet. Look for your iOS device (ex: PCMag's iPhone), tap it, and enter the password that appears on your iPhone's Personal Hotspot screen.
Source: https://www.pcmag.com/how-to/how-to-turn-your-phone-into-a-wi-fi-hotspot