Hi Yash,
Yes you can invoke a workflow on clicking save button of form by this code.
<Field name='viewOptions.Process'>
<Expansion>
<s>Your Workflow name</s>
</Expansion>
</Field>
and for sending parameters from form to workflow use
<Field name=':variables.fieldname'>
and use it in workflow simply by <ref>fieldname</ref>
Thanx
Shant