Which kind of APNS certificate should we use for In-House App Distribution?
Sandbox or production certificate?
And is there an official documentation for that?
Production, I've build many InHouse apps and production works. The sandbox only works with development builds.
I understand the confusing the Apple documentation states:
Apple Push Notification service (APNs) is available only to apps distributed through the iOS App Store or Mac App Store. Your app must be provisioned and code signed to use app services. If you are a company, most of these configuration steps can be performed only by a team agent or admin.
But the production is the one you should use for any app supplied to users. Thus also the AdHoc version.