You can use an existing virtual machine to convert into a template.

1

Start the vSphere client, and log in to the vCenter Server system.

2

From the Home page, click VMs and Templates.

3

Expand the inventory as needed, and select a virtual machine.

4

Turn off the virtual machine using the shut-down or power-off options.

5

Right-click the virtual machine and select Convert to Template.

vCenter Server marks that virtual machine as a template and displays the task in the Recent Tasks pane.