First : Enrol via Enrolment url.  When you create an add device rule into mobicontrol for IOS device at the end of the rule, it will give you a URL  (enrolment URL). On the IOS device you will need to open the Safari browser and enter the URL. This will give you a step wise enrolment guide which will finally let the device enrolled into Mobicontrol environment. 

Second Method : Enrol via enrolment ID  : For this you will need to pre-install MobiControl App from Itunes App store. Once the app is installed it will ask for enrolment ID. This ID can be obtained from the Server  IOS add device rule. 

Once you enter the enrolment id and continue with the enrolment, it will follow pretty much the same path as URL based enrolment.

NOTE : for IOS device management, having MobiControl App on device is not mandatory. The URL based enrolment can also help with managing the devices. With APP the benefit is to be able the remote view the device, Allow real time location  and access to content library documents from within the app.