Hi Sri
There are many posts for the invoice print for Customer Invoices posted through FI Transactions. I already listed one of them in my earlier responses and so have many other folks. The below link again details out the steps:
SAP19 is the standard correspondence type used for printing Customer Invoices. However, I would suggest to define a new form and assign it to a new correspondence type for your company code. You can define the form layout as per your local country and business requirements. This is how it has been done in most projects I have seen. The high levels steps for the same are as under:
1. Create a new correspondence type and assign a print program for the same
2. Assign a form to the print program
3. Create a variant for the print program for your company code
4. Now post the invoice using FB70
5. Trigger a correspondence request using FB03 for the correspondence type you have created in st 1 above.
6. Use F.62 to generate the print of the correspondence request
These are the high level configuration and transaction steps you need to perform to generate the output for Customer invoices posted through FI.
Thanks & regards
Sanil Bhandari
PS - If your query is answered, request you to close the thread so that others can benefit from the solution.