On iOS platform, you have to add app items in App-Catalog rules.  App items marked as "suggested" will not be pushed, but  rather installed on-demand by device end-user via App-catalog icon on your device home screen.     If your iOS devicesis in supervised mode, app items marked as "mandatory" will be pushed.  If your device is DEP/VPP enabled, you can deploy app items selected/purchased from the corporate VPP account without needing any AppleID associated with the device.

Thanks for your answer.

I don't know to display the list of Suggested apps on the device. Where is it? What should I do?
I don't have App Catalog icon on my device...

You should deploy the default iOS profile called "App Catalog" to your iOS device.  It is actually a web clip which points to your MobiControl server.  You might need to open this default profile and edit the web clip to fix the URL to point to something like

     https://mdm.abc.com/mc/mdm/appcatalog/%DeviceIdentifier%

(Note : replace mdm.abc.com by the FQDN of your MobiControl server)

if it has not been properly configured.

Understood! I deleted all default profiles, that is why I didn't see it :)

Thanks for your help!

Thank you for the information also from my side. Somehow the two profiles were deleted for me as well. I was already able to create the "App Catalog" web clip again. Can you tell me the URL for the Profile Catalog? I can't find anything on Google or in the manual.

This is how I created the web clip for "App Catalog":

 For the  profile catalog on Apple's device platform, edit a web clip to fix the URL to point to something like

     https://mdm.abc.com/mc/profile/%DeviceIdentifier% 

(Note : replace mdm.abc.com by the FQDN of your MobiControl server)