You can attach tags to vSphere object using vRO vAPI plug-in. It comes with some example workflows, and there is also some information online; for example, https://oliverleach.wordpress.com/2016/07/19/vrealize-orchestrator-7-vapi-vsphere-tags-workflow/
If for some reason you don't want to use vAPI plug-in, you can invoke the tagging API using the HTTP-REST plug-in.
There seems to be no vapi:vapiendpointclient type available.
I was looking to pass an endpoint client between actions but this doesn't seem possible.
Is there any reason that the vapi plugin doesn't have a type to match a client?
is there any example for objects other than "vms" ? like "standard port groups" etc...
there is seems to be no information online about objects that are not vc:virtualmachine.
The only difference would be the object ids/types, so I suppose that's why most vAPI examples intentionally do not are only for virtual machines (or some other common vCenter object type).
So if you have an example code how to assign a tag to virtual machine object, and you want to modify it to work on other vCenter object type, you just need to change the values for object type and object ID, and there is a good chance the code will assign correctly the tag to the new object.