Let's go through the following steps.
Log in to the Azure portal and search for “ App Service Domain” in your dashboard.
Click on "Create" to start.
Step 2
In this window, you can search for your desired domain. In my case, I have searched for “muhammedfasil.in” and it's available.
Step 3
If your domain name is available, you need to select Subscription, Resource group, Contact information, Privacy protection, and Legal Terms. Here, I have filled in my personal details. Next, I have accepted the privacy protection agreement. Fortunately Azure is providing Privacy Protection for free.
Step 4
In this window, you need to accept pricing. Azure Domain Service is running in association with Go Daddy.
Click "Accept" to continue.
Now that you have completed the steps, click "Create".
Azure will start deployment.
Wait for a while and click on the notification to access the service directly.
You have successfully purchased a domain using Azure App Service Domain.