Google play

Google Play gift cards are valid in the Play Store, not the Apple App Store.

See the following from https://play.google.com/about/giftcards/

Redeem gift cards easily in the Play Store app or at play.google.com

That card is for the Google Play store for Google AndroidOS tablets and phones.

Tbat card is totally useless on Apple iOS/iPadOS phone and tablet devices running iOS/iPadOS.

That card will NOT work with any of Apple's online stores, like the iTunes Store, iOS App Store, Mac App Store OR Apple's online retail products store.

Sorry.

You can redeem a Google Play card onto your Google Account on Google's website. Which you can then use to buy things like movies, Tv shows, music, or Youtube Premium, you can then use in the relevant apps on your iPad.

But you cannot redeem a google card directly on your iPad no.

Google Play is the store for Android Apps. You can't buy anything for your iPad there. And there is no iPad app for Google Play.

That's a good point, Phil. I always forget it includes things like media.