Not sure about Jamf Now, but in Jamf Pro there is a section in the Restrictions payload that will allow you to Restrict App Usage. You can choose to Allow All Apps, Do Not Allow Some Apps, or Only Allow Some Apps. We use the Do Not Allow Some Apps to hide the native apps that we don't want students to have access to (Mail, Apple Store, etc).
Having said that, we've found it to be very hit-and-miss with the Apple productivity apps like Keynote and Numbers. Sometimes it hides them and sometimes it doesn't.