You can whitelist or blacklist the system apps from Policies -> New Policy (or select an existing policy) -> iOS Settings -> App Management -> Black/whiltelisting. That’s the only way to add iOS system apps to a policy. All that you should need is a device running iOS 9.3 or a later version of iOS.
Thanks and regards
Hexnode Support Team
+1-866-498-9407 (US Toll Free)
+44-(800)-3689920(UK Toll Free)
+61-1800165939 (Australia Toll Free)
Hexnode | Mitsogo Inc.