Hi Venkata,
Well, which operation you are talking about here. Normally, workflows trigger automatically only on a standard event.
In general, if you want to automatically trigger the workflow, simply switch on event trace using SWELS and then run your transactions for operations and then check the event log in SWEL.
If there is an event found along with the workflow, then simply activate the workflow in SWDD and check if that standard workflow fulfills your business requirement.
If there is only event found and not the workflow, then you might need to create a custom workflow.
Now, here the question is, what is your requirement??? Why you want to trigger the workflow??? What do you mean by automatically triggering a message???
Richa