Link Purchase Invoice by sales invoice

i have a project and client pay down payment and create sales invoice to him
and create invoice to supplier and give him down payment
i need report to show me status for project or sales invoice
i get for example 1000$ and pay for supplier 300$
i use erpnext v 6.27

no answer
is no link between purchase invoice and sakes invoice
if no link is can create custom report show me that

Note: You have not specified all the details and have not followed standard guideline for posting on forum.

There exists link between Sales Invoices and Supplier invoice.
Standard Flow as follows:

You can customize workflow from ERPNext to make changes in standard workflow:
Read more about how to do it >