Hello @Prabha ,
Welcome to Microsoft Q&A Platform. Thank you for reaching out & hope you are doing well.
I understand that you would like to know how to integrate Application gateway with APIM (custom domain and ssl root certificate) using bicep.
You can find the ARM template/Bicep code in the below doc which shows how to integrate Application Gateway with internal API Management where API Management instance uses custom domain names and certificates are needed to configure custom domains for Application Gateway and API Management.
This template also helps deploy an App service, but you can remove that part if not needed.
The json and bicep files can be found in the below doc:
Kindly let us know if the above helps or you need further assistance on this issue.
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