You can share the internet connection from your iPad (Wi-Fi + Cellular) with other devices using a feature called Instant Hotspot. Instant Hotspot uses your iPad device’s Personal Hotspot, and is useful when your other device doesn’t have internet access from a Wi-Fi network.
There are several ways to connect other devices to your Personal Hotspot:
Connect your Mac to your iPad through Wi-Fi settings.
Pair your two devices with Bluetooth®.
Connect your Mac to your iPad with a cable.
You can share the Personal Hotspot on your iPad with another iPad, an iPhone, a Mac, a Windows device, and more.
Note: Personal Hotspot isn’t available with all carriers. Additional fees may apply. The number of devices that can join your Personal Hotspot at one time depends on your carrier and iPad model. Contact your carrier for more information.
Make sure of the following:
Both devices have Bluetooth turned on.
Your devices must be within 30 feet (10 meters) of one another.
See the Apple Support article Apple Support article: About the ‘Trust This Computer’ alert