How delete purchase history?

"

Learn more

• Hiding an app doesn't cancel a subscription. Learn how to view, change, or cancel your subscriptions.
• Hiding an item doesn't hide the record of purchase. You can view your purchase history to see details of your purchases."

None of Apple's documents mention in-app purchases specifically, but it does read the same for both sets of documents (the link above and a link off that link for media purchases) covering hiding purchases. In other words I don't think you can hide them in your purchase history, just in your possible download listing.

Hide and unhide apps for your iPhone, iPad, iPod touch, or Mac ...

You are welcome to double check but I think the same will apply to the view from a computer. You can't hide purchase history. You can hide from list of available downloads.