How does a PAM process know which Object ID called invoked/triggered it based on an event and/or macro? Is it the same whether it's the "Request Area" workflow property that kicks it off versus another event/macro combination?
SDM always passes the persistent_id of the object triggering the process.
Look for Process.persid
The integration passes that information from Service Desk into Process Automation when you launch a process from a Category or event.
You can get more details on setting up an event macro in the documentation for Service Desk or in the following Knowledge article.
Retrieving data ...