I am trying to use Quick Add Feature when I am enrolling my laptops. I have Mojave 10.14.6 installed on my laptops. I go to enroll them, got the Quick Add pkg, it installs the Quick Add but when it is complete, it says "The Installation Failed" Contact Software Manufacture for assistance. I go into JAMF Pro and the computer is listed but it will not say anything on Last Computer Checked in.
Can I ask why you want to use a QuickAdd pkg instead of the profile based method? The thing about Mojave, and actually with High Sierra before it, is that enrolling with a QuickAdd will leave you with an MDM profile that is not fully approved and therefore missing some functionality. The user will need to go into Profiles and approve it to get it fully enabled. Using the direct profile installation method and user initiated enrollment bypasses that issue. So does automated enrollment with Apple Business/School Manager (what used to be called DEP).
Basically, Jamf doesn't recommend using a QuickAdd pkg anymore with current OSes. I'm not necessarily saying that's the reason for the installation failure, but you should try to use a different method if possible.