Assuming that both your iPad and iPhone are signed-in to iCloud with the same AppleID, your iPad will be able to automatically connect to your iPhone's hotspot connection.
On your iPad:
Settings > WiFi > Auto-Join Hotspot - set to Automatic
When correctly configured, your iPad will connect to your home (or other known) WiFi networks when within range - and automatically switch to using your iPhone's hotspot. When linked to the iPhone hotspot, your iPad will be using your iPhone's Cellular data.
Many users choose to have a WiFi+Cellular iPad in preference to the slightly cheaper WiFi Only model - even if they have no immediate need or intention of provisioning an additional Cellular plan for their iPad. The two primary reasons are:
1) You have benefit of GNSS/GPS functionality that it not available to WiFi Only models. This provides the means to obtain accurate location - regardless of having a network connection - which will be of importance to you if using moving maps or other Apps that require precise location data.
2) You can easily add a Cellular plan to your iPad - directly from iPad settings using the built-in eSIM - should your needs change in the future.