# 33. OPP (Outside Part Purchases)

OPP lists every part on the [invoice](https://autosoftware.company/invoice_entry_form.php) with its [outside part purchase](https://autosoftware.company/osp_parts_form.php), if it has one: the Expense#, Expense Date, Cost, Sales Price, Supplier, Supplier Invoice#, Part Name, Part#, Payment Type and Description. Recording what you paid the supplier for a part gives the invoice its true profit, and your shop may require it before the invoice can be finalized.

## How do I record the cost of a part bought from a supplier?

1. From the Home Screen, click Invoices → Invoice List and open the invoice.
2. Click OPP.
3. Click Add beside the part. The outside part purchase form opens in a new tab.
4. Enter the supplier, supplier invoice number, cost and payment, and save it.
5. Back on the invoice, click OPP again. The part now shows its Expense#, and the button reads Edit.
6. Click PRINT OPP to print the list.

![OPP History](/images/s139_ba9839b7.png)
*OPP History*