can I fax in invoice to a customer directly from Quickbooks?

Hello there, Central Countertop.

I can provide information about faxing an invoice in QuickBooks.

The option to fax in an invoice to a customer directly from QuickBooks is unavailable. This can only be possible if you look for a third party app that has this functionality. There are several third party apps that you can choose from in our QuickBooks Online Apps center. Otherwise, you'll look from outside QuickBooks.

Feel free to check these handy articles for future reference in recording customer payments and customizing sales forms in QuickBooks:
 

• Record invoice payments in QuickBooks Online
• Customize invoices, estimates, and sales receipts in QuickBooks Online
   

 I'm always here to help you if you have clarification with managing your invoices and faxing in QuickBooks.

@Central Countertop 

You need a 3rd party solution.