IPad Storage
I have no storage available on my iPad. I did set up photos to be uploaded to iCloud and to "optimize iPad storage" but it didn't free up any storage. How can I get more storage?
iPad Pro 11-inch Wi-Fi
The iPad’s storage is not internally expandable. The Pro models can use external drives.
this is how to check your internal storage
How to check the storage on your iPhone, iPad, and iPod touch - Apple Support
Connect external devices or servers with Files on iPad - Apple Support