For the operators how can we find the tasks are assigned by manually or next assignment. Can you please let us know is there any OOTB report is there or can we do create any report. Can you please suggest to me.
You have to clarify what you mean by next assignment or manual. Ultimately, they both end up being instances of assignment objects (Assign-Worklist presumably). To determine if there is a difference you could create assignments by both means and compare the attributes on the assignment object instances. Possibly the pxCreateOperator attribute may differ. The audit trail for the case (History-Case class) may hold some information as well but I am not sure offhand if it would contain the information you need.