Hi Charanteja,

I have Gone through your question major difference between the Workflow and trigger:--


Workflow:-Work flow triggers when a DML event like Insert, Update Occurs.we can't fire workflows after the record has been deleted.



Workflow actions are     Field Update, Email alert, Task alert, and outbound message........ so u can any of action for workflow.so whenever workflow fires that action takes place.



Approval Process:-

suppose u can think like this, in a Software company there is an HR team whenever they open a position, that position has to approved by HR team..if Hr team approved that position then that position is approved and they start open recruitment. if they rejected  position then they doesn't open recuritment.........for that position



whenever a record submitted to an Approval process, the record is going into locking state.if it is approved then it is in locking state forever. if it is rejected then that records come into an unlocking state.



in the approval process, we can trigger workflow when initial submission, approval action, rejection action, final rejection.................





Trigger:-  Trigger is also the same, when a Dml event occurs like insert, update, Delete trigger will fire......

here in deletion Scenario also trigger will fire....but in workflows workflow cannot fire..........for deletion



I hope you find the above solution helpful. If it does, please mark as Best Answer to help others too.

Thanks and Regards,
Deepali Kulshrestha
www.kdeepali.com