iPad Pro 12.9 (2021)
It's not possible to use Wi-Fi
Solution 2 of 4: No connection to a Wi-Fi network is established
You can use Wi-Fi as an alternative to the mobile network when establishing an internet connection. This way your tablet doesn't use mobile data.
Press Settings.
Press Wi-Fi.
Press the indicator next to "Wi-Fi" to turn on the function.
Press the required Wi-Fi network and key in the password for the Wi-Fi network.
Press Join.
Slide your finger upwards starting from the bottom of the screen to return to the home screen.