Normally a process starts with Receive Step which listens to a publishable document. To initiate the process, you publish the document (or event) from somewhere.
Let say I publish the doc from a service by invoking pub.publish:publish.

My question: is it possible to invoke pub.publish:publishAndWait to wait for the reply back from the end of the process?
The process does not involve Task but just calls a series of services.

Jola:-

You can easily get the sync response back from the the BPM. Generally publish is async and but if in deed have some webApps that invokes the BPM sync until bpm have sync reply back it can reply back the response.

I had used the ublishAndWait for getting the reply as sync apps especially for UI based applications.

One way of doing this is to use pub.publish:reply service in the flow service that you write for the step which takes in the document that you publish.

Yes it is possible,

You can use the publish step as the termination step of the BPM.