Hi Abhisekh,
You will need ABAP program and BTE 1650 to add fields in FBL1N.
What you are trying to do will work only if you have a 1:1 relationship, this means 1 material : 1 Invoice. Another approach will be through FBL3N (but you will have to get the report for all entries and then filter by vendor) or a custom program and get your information.
Kind Regards