How
to create an Azure AD or Azure Tenant
First
create a outlook account
Sign in
with that account
Reach this URL to name your tenant
https://portal.azure.com/#create/Microsoft.AzureActiveDirectory
Use an existing Azure AD tenant
Many developers already have tenants through services or subscriptions that are tied to Azure AD tenants such as Office 365 or Azure subscriptions. To check if you already have a tenant, sign in to the AzurePortal with the account you want to use to manage your application and check the upper right corner where your account information is shown. If you have a tenant, you'll automatically be logged into it and you'll see the tenant name directly under your account name. If you hover over your account name on the upper right-hand side of the Azure portal, you will see your name, email, directory and tenant ID (a GUID), and your domain. If your account is associated with multiple tenants, you can select your account name to open a menu where you can switch between tenants. Each tenant has its own tenant ID.
Create a new Azure AD tenant
If you don't already have an Azure AD tenant or want to create a new one, you can do so using the directory creation experience in the Azure portal. The process will take about a minute, and in the end you'll be prompted to navigate to your newly created tenant.
NOTE:
If you need to find the tenant ID, there are multiple ways to find this info. You can hover over your account name to get the tenant ID or you can select Azure Active Directory > Properties > Directory ID in the Azure portal.
Reference:
https://docs.microsoft.com/en-us/azure/active-directory/develop/active-directory-howto-tenant#create-a-new-azure-ad-tenant
