Normally how many rounds of interview & session have been done to finalize a candidate for a position?

It totally depends on HR policies of companies some comanies just take two rounds.

if candidate is out of location a telephonic round and then next a face to face interview.

Some sectors take5/6 rounds as well.

1) Written test2) Personal Interview3) Group discussions4) Manager level  5) Head of Department round  6) HR level for finalization and negotiation on salary and sometimes Director level as well if its for mid level - jobs like supervisors, team leaders, asst managers