how do i populate the required field vale in form header

[vits18735a0]

dear community,

i created  custom table and i did not have any autonumber field in that, but i created one customer field and it will generate a number when ever user saves the record. i want to populate that field value below the table name in form header. but right now i am seeing the created on field value. 
from where it is populating?

Thanks,

chandu ram