Rather than juggling your email browser, you can send vendors their Purchase Orders from the QuickBooks Commerce app. Seamlessly communicate with customers to make your daily administrative tasks easier.
You can mail a Purchase Order at both 'Active' and 'Received' stages.
Go to the Purchase Order that you wish to send;
Click on the Email button located at the top of the page.

A dialogue box will appear. Enter the recipient’s email address and a cover message. A PDF copy of the Purchase Order is automatically attached.

Click Send to send the Purchase Order.
Simple! That is precisely what QuickBooks Commerce aims to do for you. You can also Print and Save a Purchase Order by following the instructions here.
You can also customize your email template for purchase orders (and more). Learn how to do so by following the instructions in this article.