Azure Virtual Network (VNet) is a foundational component in Microsoft Azure that enables secure communication between Azure resources, external networks, and on-premises environments. It allows you to create a logically isolated network in the Azure cloud.
To create an Azure virtual Network with four subnets using the address space 192.148.30.0/26, the following steps are required.

Steps to Create a Virtual Network with Four Subnets in Azure Portal

Step 1: Log in to Azure Portal

• Navigate to Azure Portal and sign in with your credentials.

Step 2: Create a New Virtual Network

• In the search bar at the top, type "Virtual Networks" and select it from the results.

• Click on (+ Create) On the Virtual Network page

Step 3: Define Basic Settings

• Subscription: Select the subscription to use.

• Resource Group: Choose an existing resource group or create a new one.

• Virtual Network Name: Provide a name for the VNet.

• Region: Select the region where you want the VNet to be created.

Step 4: Define Address Space

Step 5:Click + Add subnet to define each subnet

• Subnet 1: Name: Finance Department

• Subnet 2: Name: IT Department

• Subnet 3: Name: Admin Department
  

• Subnet 4: Name: Accounting Department

Step 6: Review and Create

• Click Review + Create.

• Click on go to Resource

• Click on setting blade and navigate to subnet and see the four Subnet created

CONCLUSION
Using the Azure virtual network, Proper planning of IP address ranges is essential to avoid overlaps and ensure efficient use of resources. This structure enables robust application deployments, fosters compliance with organizational policies, and supports integration with on-premises environments through tools like VPN or ExpressRoute.