Inter Company Invoices
An Inter Company Invoice is a record of business done between two companies that are part of the same corporate group. With ERPNext, you can make linked Sales and Purchase Invoices between these kinds of companies. This helps you keep your intercompany accounting clear and correct.
For example: You can make a Purchase Invoice for Company ABC and a Sales Invoice for Company XYZ, and link them both to show the internal transaction.
1. How to Make Invoices Between Companies
1.1 Steps to Set Up
A. Set Up the Internal Customer

Go to Accounts > Master > Customer.
Choose or make the Customer that stands for the other company inside.
Check the box that says Is Internal Customer.
Choose the company that this customer works for in the Represents Company field.
Add the company that this internal customer (the buyer) will do business with to the "Allowed To Transact With" table.
B. Set Up the Internal Supplier

Go to Accounts > Masters > Supplier.
Choose or make the Supplier.
Check the box that says Is Internal Supplier.
In the Represents Company field, choose the company that this supplier works for.
In the Allowed To Transact With table, put the name of the company that this supplier will do business with (the seller).
Note: To make sure the links work, make sure the Customer and Supplier setups are the same.
1.2 Before Making the Invoice: Setting Up a Price List

Before making an invoice between companies, make sure that both the buying and selling companies use the same Price List:
Click on Stock and then Price List.
Make a new Price List, like Inter Company Price List.
Check both: Buying and Selling.
Give this Price List to:
The Internal Supplier (in the Buying section).
The Internal Customer (in the Selling section).
1.3 Making Invoices Between Companies
Option A: From Sales Invoice → Make a Purchase Invoice
Make a sales invoice for the company that is selling.
Choose the Internal Customer.
Fill out the information and send in the invoice.
Choose Inter Company Invoice from the Make button.
ERPNext will automatically make a linked Purchase Invoice for the buying company with the right information about the company and the supplier.
Check the Purchase Invoice and then send it.
Option B: Create a Sales Invoice from a Purchase Invoice
You can do the same things in reverse:
Use the Internal Supplier to make a Purchase Invoice for the company that bought it.
Send it in.
To make a linked Sales Invoice for the seller, choose Make > Inter Company Invoice.
Important Notes:
A company can only have one Internal Customer or Supplier.
If you cancel one invoice, the other one will no longer be linked.
Intercompany invoices only affect the accounting ledger, not the stock ledger, because both companies are in the same group.