To post invoices with project codes, please follow the steps below:
Open Setup, General Setup, Transactions.
Tick to select Project by Bill
OK.
Go to Customer & Sales, Sales Invoice, Create Invoice.
Fill in the details and also select Additional and fill in the Project codes.
You may add the new project code here. Type in any code (maximum 4 characters) and hit 'enter' on the keyboard.
Click on 'Yes" to create a new project code.
Save the new project code details and proceed to complete the invoice.
Select Post to Accounting to complete the posting of the bill with project codes to accounts.