See:
Apple AirPrint is a driverless connection protocol. A high proportion of modern printers intended for Home, SoHo and Business environments now support AirPrint.
About AirPrint - Apple Support
If your printer supports AirPrint - and is set-up correctly - should you continue to experience difficulties your WiFi Router may be unexpectedly failing to pass Apple Bonjour traffic on you local network - or your WiFi Router or Network Switch may be blocking this (or other) device discovery protocol(s).
You may find that a restart of your network components will resolve the problem. You’ll need to restart your network devices in the correct order. Assuming that you WiFi Router provides DNS services for your network, restart devices in this order - allowing time for devices to fully boot/restart prior to restarting other devices:
- WiFi Router
- Upstream wired Network Switch(es) (if any)
- WiFi Access Points / Network Extenders
- Other fixed infrastructure devices - such as Printers
- Client devices (your iPad)
Restarting your iPad, after restarting other devices in the correct sequence, is most simply achieved by a restart of your Apple devices:
Force restart iPad - Apple Support
Force restart iPhone - Apple Support
Shut down or restart your Mac - Apple Support
If you continue to have difficulties, check to see if your iPad/iPhone are using the new WiFi Private Address feature. This feature is intended to provide additional privacy and security when using “public” (untrusted) WiFi networks.
Settings > WiFi > [Your WiFi Network / SSID] - tap the “i” icon - Private Address
The Private Address feature is largely unnecessary for your home WiFi network; if enabled, Private Addressing can interfere with anticipated operation of other devices, such as AirPrint/Airplay. In such circumstances, you may need to disable this feature - and can be enabled or disabled for each individual network.
Use private Wi-Fi addresses in iOS 14, iPadOS 14, and watchOS 7 - Apple Support