I purchased 200gb of data and it shows in ICloud. My IPad keeps saying IPad storage full. How do I get the iCloud gb to connect to iPad storage?

It is impossible to increase the amount of internal storage in your iPad - as this is fixed during manufacture; what you have is fixed for the life of your device. 

You can, however, subscribe to a higher tier of iCloud storage - but this is not a substitute for internal storage.

About storage on your device and in iCloud – Apple Support

Manage your iCloud storage – Apple Support

If you have insufficient internal storage for your needs, you have two options:

• Manage the storage that you already have:

How to check the storage on your iPhone, iPad and iPod touch – Apple Support

• Replace your iPad with a model with adequate storage for your needs.

You'll need to "allocate" the local data that you want to save on iCloud instead. First go to Settings>General>iPad Storage to find out what's taking up all the local space. If you have a lot of photos, you can turn on Photo in iCloud settings which will decrease local file resolution to significantly reduce the space it takes. If you have a lot of apps, try Offload Unused Apps in iPad Storage. If you have a lot of documents, etc, you can move them to iCloud in the Files app.

You cannot purchase extra storage (or “data” as you call it) for an iPad or iPhone. You’ve bought extra iCloud storage. As the previous answer suggests, you may be able to make some use of that extra cloud storage to free up space on your device, but this is limited, and you may already be doing that anyway.