Hi Arun,
It is pre-notification to Customer to pay outstanding items which will pay next 14 days. It is not possible to generate pre- notification through F110.
Solution :- Go to FB00 > Line items > Select Selection by due date check box and save.
Go to FBL5N report where you can see the Net due date in selection field & Create customer wise back ground job. ( It is too difficult ,if customers are more )
Other solution is :- Better to use Dunning or else custom development.
Regards
Mani