Add Network Interface of Virtual Machine to Application Security Group

See the explanation below.

1. In the Search resources, services, and docs box at the top of the portal, begin typing the name of a virtual machine, VM1 that has a network interface that you want to add to, or remove from, an application security group.

2. When the name of your VM appears in the search results, select it.

3. Under SETTINGS, select Networking. Select Configure the application security groups, select the application security groups that you want to add the network interface to, or unselect the application security groups that you want to remove the network interface from, and then select Save.

https://docs.microsoft.com/en-us/azure/virtual-network/virtual-network-network-interface

Sure, here's a step-by-step guide on how to add the network interface of a virtual machine to an application security group using the Azure portal:

1. First, navigate to the Azure portal by typing portal.azure.com into your web browser and sign in with your Azure credentials.

2. Once you're signed in, search for "Virtual machines" in the search bar at the top of the portal, and click on the "Virtual machines" option that appears.

3. Find the virtual machine named VM1 that you want to add to the application security group. Click on the virtual machine to open its details page.

4. On the virtual machine's details page, click on the "Networking" tab.

5. Under "Networking interfaces," click on the network interface that you want to add to the application security group. This will open the details page for the network interface.

6. On the network interface's details page, click on the "Configuration" tab.

7. Scroll down to the "IP configurations" section and click on the name of the IP configuration.

8. On the IP configuration details page, scroll down to the "Application security groups" section and click the "+ Add" button.

9. In the "Add application security group" pane, select the application security group named ASG1 that you want to add the network interface to, and click "Add".

10. Click "Save" to save the changes you've made.

That's it! You've now added the network interface of VM1 to the ASG1 application security group.