Hello @SteveT , unless you have some kind of gateway that router traffic to your IIS, applications hosted in IIS need SSL certificates installed and bound on IIS, not in Azure. You can also use Azure Key Vault to securely deploy certs to your Azure Windows VM. Follow the steps detailed in Tutorial: Secure a web server on a Windows virtual machine in Azure with TLS certificates stored in Key Vault. If you run into additional issues share error details and/or screenhosts so we can assist.
Let us know if you need additional assistance. If the answer was helpful, please accept it and rate it so that others facing a similar issue can easily find a solution.