Hello Anjali,
We have done a similar development where the BIlling date should be prior to Delivery date.
You will have to sepak to your ABAPer & insert a ABAP code in Enhancement spot in Program SAPMV60A. This ABAP code will check for the billing date in Invoice & check whether the date is Equal to today's date or yesterday's date & give a error message if Billing date is not today or yesterday.
Thanks,
Jignesh Mehta