What's the best way to match vendor invoices to customer order numbers in QBs?

Hello, llevy. 

Thanks for checking this with the Community. You'll can convert the estimate to an invoice. An Estimate is a proposal for something for a specific price that you can be turned into an invoice. 

To create an estimate:

1. Click the + New icon, then choose Estimate. 
2. Enter the needed details.
3. Click Save.

To convert an estimate to an invoice:

1. Open the estimate.
2. Click the Create an invoice button. 
3. Update if needed.
4. Tap Save and close.

You can find more information about estimates in these articles:

• How to convert an estimate/quote into an invoice
• Estimates/Quotes

Count me in if you need further assistance. Take care!

Thanks for your reply. My client is not using QBs for estimates or proposal. Lke a class or category, is there some good function of QBs for matching and reporting things order by order?

Thank you for getting back to us, @llevy. I'll help you resolve the issue.

The option to match vendor invoices to customer order numbers in QuickBooks is unavailable. However, we can utilize the custom fields where you can manually enter your order numbers to track the invoices.
 

Users can add up to three additional custom fields to their invoices in QuickBooks Online. This feature can be enabled in Company Setting. You can use these fields as report columns when running related reports.
 

Here's how to set up custom fields:
 

1. Go to Settings, then select Custom fields.
2. Select Add field.
3. Choose and enter a name in the Name field.
4. Click on the All Sales forms checkbox.
5. Select Print on Form if you want the custom fields to appear on printed and delivered forms.
6. Then select Save.
    

For additional information, you can click on this article: How to add custom fields to sales forms and purchase orders.
 

If you want to create and edit custom fields in QuickBooks Online Advanced, you can click here. 
 

Please come back if you have any additional information or clarification. I'll be happy to guide you. Keep safe!