By default, the website will be available on an auto-generated domain via https protocol.
To configure a custom domain you would need to do the following:
To enter a custom domain, go to the environment, in Resources, click the Website resource, then in Resource Settings find the DomainName parameter.
To create an SSL certificate follow the How to create SSL certificate guide.
The certificate should be created in N. Virginia region.
Make sure that the domain name specified in the certificate matches the domain name provided in the Website resource from the previous step.
Click on the Save button to only save these changes, or select the Save and Deploy button to apply the changes in the cloud.
In the Website resource > Overview tab, under Resource Outputs, you should see the value of the CNAME parameter. Copy this value and add it as a CNAME record in your DNS provider.