As part of the handover, besides the Deployment Workbook, you should have several files, including AzureStackStampInformation.json.
This file is automatically created at the end of each Azure Stack Hub deployment and contains a post-deployment summary of the Azure Stack Hub environment. It contains all the endpoint addresses for the environment, including the tenant and admin portals. The following figure shows an example:
Figure 4. Example of post-deployment summary
If this file is not available, the portal URL is based on a combination of the region name and external fully qualified domain name (FQDN) of your Azure Stack Hub deployment.
For example, if the region name is rack01 and the FQDN is dellemc.net, then the portal URLs are similar to the following list: