How to verify AppleCare+ is activated on my iPad Pro?

You can check your Apple warranty coverage here:

Check Your Service and Support Coverage - Apple Support

If you need assistance to verify that your AppleCare+ plan has been correctly applied, you would be best advised to seek assistance directly from Apple Support. You can contact the Support Team using the Support link at top-right or bottom-left of this page.

Alternatively, you can initiate and manage your support cases from Apple devices using the excellent Apple Support App. If not already installed, the App can be downloaded from the App Store:

https://apps.apple.com/app/apple-support/id1130498044

Did you already contact the official Apple Support about it?

Contact Apple for support and service - Apple Support

Usually you will also get your Apple Care+ contract details by email from Apple.

Did you pay upfront for the Apple care or select the monthly plan?

I had the same problem when I pre-ordered the iPad - I purchased the monthly plan at the same time. When I received the device I found AppleCare not activated. I contacted customer service several times but either they didn’t know what I meant & wanted the confirmation/contract email which I hadn’t received as it hadn’t been activated or I was told it could take 48 hours to activate. It didn’t so ended up having to choose to purchase monthly again. Thankfully I’m not paying twice.