If you notice that your Bluetooth or Wi-Fi settings are grayed out on your iPad, restart your iPad and make sure that you are not in Airplane Mode. To check that, tap on Settings, and then Airplane Mode. If your Wi-Fi is still grayed out, then reset your network settings by tapping on Settings, General, Reset and then Reset Network Settings. This option will reset all of your network settings including Wi-Fi passwords, VPN and APN settings as well as Bluetooth pairing records.
If the Wi-Fi Settings on your iPad are still grayed out after you have restarted the device, made sure you were not in Airplane Mode and reset the network settings, then you will need to contact Apple support to see what else may be done to regain access of your Wi-Fi settings.