Hi Sonu,
The 'Approval' and 'Approval Set' fields are the OOB fields on the task table.
It's available on project table because 'pm_project' table extends 'planned_task' table and 'planned_task' extends 'task' table. So by inheriting the fields of parent table Project table has these two fields.
Approval: This fields reflects the status of approval generated for the record.
Approval Set: This field is used to set the date/time when the Approval was approved.
Since, you are not having any approval on Project table so you can ignore this fields.
Kindly mark my answer as Correct and Helpful based on the Impact.
Regards,
Alok
