I know it is possible to dial an extension after you have dialed a phone number from an app but I am not finding a way to add *67 or call blocking in front of a phone number for my IOS app. I have tried different variations of this but nothing has worked. Does anyone know if this is possible or does Apple not support such a feature?
No, it is not possible.
You cannot make the iPhone dial a *
or a #
using a tel
URL. Apple documents its support for tel
URLs in the Apple URL Scheme Reference, which says this:
Specifically, if a URL contains the
*
or#
characters, the Phone app does not attempt to dial the corresponding phone number.