In  order to understand what is Azure Entra ID please refer the below article:

Step 1: Accessing Azure Entra ID

To begin creating tenants you would need to access Azure Entra ID, the underlying service that powers identity and access management in Azure.

Follow these steps:

• Log in to the Azure portal using your administrator credentials.
• Under Azure Services, select Microsoft Entra ID

Step 2: Creating a New Tenant

• Once you are in Microsoft Entra ID you can select Manage Tenants

• Under Manage Tenants you can select Create

• You can select the Type of Tenants from Microsoft Entra ID or Azure AD B2C

• Once selected you can click Next:Configuration

• Here you can mention the Organization Name, Initial Distinguish Name, Location, Resource Group and Resource Group Location.
• Once done select Next: Review + Create.
• Here you can review the configuration and click Create

• Once done you will be able to see your next tenant being created, You can monitor the task under Notifications as below

• Once done you can navigate into your newly created Tenant:

Creating tenants in Azure Entra ID is a fundamental step towards establishing a secure and efficient cloud environment in Microsoft Azure. By following the steps outlined in this guide, you can set up and configure tenants to suit your organization’s needs, empowering you to maximize the benefits of Azure’s robust cloud platform. Whether you’re a small startup or a large enterprise, Azure Entra ID provides the tools and capabilities you need to thrive in today’s digital landscape.