Software Update iOS
Why don’t the Software update option shows on my iPad?
iPad Pro, iPadOS 13
You might be running a beta iOS version on your iPad.
Should be this case, see these instructions:--> How to uninstall iOS or iPadOS beta software - Apple Support.
Shouldn't be this case, identify your model correctly, using this support article:--> Identify your iPad model - Apple Support, then see this compatibility list: