It's been awhile so I completely forgot how to convert an iPad that was original not purchased under the Business Manager to a DEP iPad. I know you have to use the Apple Configurator.
Solved
Convert non-DEP iPad to DEP?
+8Best answer by pchimombe
Enrol using Apple Configurator then log into your ASM/ABM search for the device and assign it to your JAMF Server.
+7Enrol using Apple Configurator then log into your ASM/ABM search for the device and assign it to your JAMF Server.
+8@mwu1876 Here is the link that I used to enroll my iPads manually.
Then you enroll them you will go to ASM or ABM to assign it to your MDM Server.
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.