You can use the vSphere Automation APIs to create virtual machines depending on your needs and infrastructure setup.
You can create a basic virtual machine and then configure it according to your needs. You can also create a more comprehensive virtual machine and then edit its settings. To create a virtual machine, you must specify the datastore, resource pool, folder, or host where the virtual machine is placed. Later, you can customize the virtual machine by specifying the boot options, number of CPUs, the guest OS, and virtual NIC. See Creating a Virtual Machine Without a Clone or Template and Configuring Virtual Machines.
You can use a turned off virtual machine to create a VM template from which to deploy other virtual machines. See Create a VM Template in a Content Library from a Virtual Machine. You can also mark a virtual machine as template by calling the VirtualMachine.MarkAsTemplate
method from the vSphere Web Services APIs. See vSphere Web Services SDK Programming Guide.
You can capture a virtual machine or a vApp in an OVF template and store the template in a content library. Then you can use the OVF template to deploy a virtual machine or a vApp in your environment. See Creating Virtual Machines and vApps from Templates in a Content Library.