Step 1: Download a Certificate Signing Request from Windows Intune using the Request APNs Certificate Service Request dialog ...

Step 1: Download a Certificate Signing Request from Windows Intune using the Request APNs Certificate Service Request dialog box in the Configuration Manager console.

Step 2 : Submit the Certificate Signing Request to the Apple Push Certificate Portal and download the APNs certificate. 

Step 3: Upload the APNs certificate to Windows Intune by specifying the location of the APNs certificate.