Is there a way to send an invoice and attachment as one PDF file to a customer

Hi mowill123,

I can see how having this feature would be beneficial for you. At this time, QuickBooks Online only allows you to send just an invoice. The most you can do is edit/add customized text to your invoice message like the image below: 

I encourage you to send feedback about this to our engineers by clicking the Gear icon and looking for Feedback. We appreciate any feedback we get from users like you because that's what makes the product better. In the meantime, feel free to ask questions. I'm here to help.