I want to know which API need to use in vSphere Client 6.7 to create a new virtual machine using a template.Would '/rest/vcenter/vm-template/library-items/{template_library_item}?action=deploy' this API will solved my issue. And How to find the required parameters that need to pass in the rest API
For exploring the vCenter Server rest APIs, you can go to the vSphere Client -> Home -> Developer Center -> API Explorer. There you may find all information about the different APIs.