iPhone Hotspot wi-fi or bluetooth ?
Connecting iPad to iPhone hotspot. Which way is best wi-fi or bluetooth?
iPad (7th generation)
You can access your iPhone's hotspot wirelessly using WiFi or Bluetooth - or directly using a wired connection between the device's Lightning/USB-C ports.
Your iPad will automatically use the iPhone's WiFi hotspot - this providing best throughput and connection stability.
See:
How to set up a Personal Hotspot on your iPhone or iPad - Apple Support