Procreate for ipad ($9.99 paid version) is it available for family sharing?

Some apps offer additional purchases from within the App, such as ongoing subscriptions or additional items like gems, or upgrades for games or a "no ads" option for free apps.

Those types of purchases made after the app has been downloaded are generally not shareable over Family Sharing.

In the case of Procreate it does not have any in-app Purchases so it does not apply.

Yes. As per the section in the Apps details referring to Family Sharing: https://apps.apple.com/us/app/procreate/id425073498