How to deploy DMG or APP-format apps to Intune-managed Macs

Can anyone point me in the right direction for finding the info highlighted in bold for step 6.

productsign --sign “3rd Party Mac Developer Installer: Developer Name (XXXX)”./unsigned_final.pkg ./signed_final.pkg​

We are deploying Photo Mechanic so I'm assuming it's:

productsign --sign “3rd Party Mac Developer Installer: VideoLAN (XXXX)”./unsigned_final.pkg ./signed_final.pkg​

Just not sure how to get the cert number part e.g. (XXXX)

*** EDIT MAY 28 2022 *** 

I'm posting an update as I have made progress since the last post.

To perform step 6. you need to have an Apple ID that is enrolled in the Apple Developer program and create an Apple Developer ID Installer Certificate.

Apple Developer program
This Apple support article outlines the steps for how to enroll in the Apple Developer program:
https://developer.apple.com/support/app-account

The Apple Developer Program annual fee is 99 USD and the Apple Developer Enterprise Program annual fee is 299 USD, in local currency where available.

Apple Developer ID Installer Certificate
When you have an account enrolled in the Apple Developer program, the next step is to create an Apple Developer Installer Certificate as outlined in the following guide:
https://forums.ivanti.com/s/article/Obtaining-an-Apple-Developer-ID-Certificate-for-macOS-Provisioning?language=en_US&ui-force-components-controllers-recordGlobalValueProvider.RecordGvp.getRecord=1#:~:text=Creating%20the%20Certificate%20(XCode),and%20select%20Developer%20ID%20Installer.

I have now performed the above steps and added the certificate to my keychain and was able to sign the package with:

productsign --sign "Publisher Name (XXXXXXXXXX)" ./unsigned_final.pkg ./signed_final.pkg​

I then uploaded the pkg to intune and it deployed successfully. I will now be performing this with the other 7 apps I need to deploy.

I am very happy this is working now 🙂