Start with basic WiFi troubleshooting - as detailed here:
If your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network - Apple Support
Recommended settings for Wi-Fi routers and access points - Apple Support
If your WiFi has been set-up according to Apple’s recommended settings, WiFi and Internet connection difficulties are usually an indication that your device/computer does not have a routable IP Address - your IP Address usually being assigned by DHCP - or something is blocking access to some internet resources. When this occurs, your iPad may only have a self-assigned link-local IP address that begins 169.254.x.x.
If you are using a VPN connection, or a security App such as Norton etc., these may be (a) interfering with DHCP and preventing your device from obtaining a valid IP Address, or (b) blocking access to some external resources. For this, the resolution is usually simple; if installed, you may only need to temporarily disable or remove the Security App and/or VPN.
If this resolves your issue, the VPN and/or security App can be reinstated after the connectivity problem has been resolved.