Connecting your iPad to WiFi is the primary method of connecting your iPad to a network and the internet. WiFi+Cellular devices also have capability of connecting to a Cellular network:
Connect to Wi-Fi on your iPhone, iPad, or iPod touch - Apple Support
Set up cellular data service on your Wi-Fi + Cellular model iPad - Apple Support
If you experience difficulty connecting to your WiFi network, these support resources should help with troubleshooting:
If your iPhone or iPad won't connect to a Wi-Fi network - Apple Support
Recommended settings for Wi-Fi routers and access points - Apple Support
If instead you wish to connect your iPad to a wired Ethernet network, you will need a compatible Ethernet adapter for your iPad...
An iPad with a USB-C port will require either a compatible USB-C hub that includes an Ethernet port - or a dedicated compatible USB-C Ethernet Adapter. For example:
https://eu.ugreen.com/collections/ethernet-adapters/products/ugreen-usb-c-to-ethernet-adapter?variant=40343590469715
When purchasing a USB-C hub or adapter for iPad, ensure that the manufacturer explicitly states compatibility with iPadOS.
If your iPad has Lightning port, you will either need to identify a Lighting to Ethernet Adapter (e.g., Belkin) - or use a Lightning to USB3 Camera Adapter and a USB Type-A to Ethernet Adapter:
Lightning to USB 3 Camera Adapter
https://store.apple.com/uk/xc/product/MK0W2ZM/A
USB Type-A Ethernet Adapter
https://eu.ugreen.com/collections/ethernet-adapters/products/ugreen-aluminum-usb-3-0-lan-ethernet-adapter?variant=40343584735315
For Lightning devices, chaining the two Adapter's may be the more versatile and more reliable option - as you will have benefit of just using Apple Lightning USB3 Camera Adapter when you need to connect USB Storage or other compatible USB devices to your iPad - plus you may already have the Apple Adapter.
