How do I setup iCloud storage?
How do I backup iPad photos to my cloud?
iPad Air 2, iPadOS 13
You may want to consider syncing them to iCloud via iCloud Photos. See instructions in: Set up and use iCloud Photos - Apple Support
Syncing has the benefits of automatically syncing any changes, being able to sync to other devices if you want to, and being able to view the photos at www.icloud.com.
If you don't want to turn on iCloud Photos, you can backup instead -- see instructions in How to back up your iPhone, iPad, and iPod touch - Apple Support