Per Product Emails Documentation

EDD sends an email to the purchaser with every sale. Per Product Emails allows you to additionally send a custom email for any given product.

Once installed, you'll find a new menu item called "Per Product Emails" under the Downloads menu in your WordPress dashboard. Once there you can choose Add New and you'll find an interface exactly like the default email configuration tool in the EDD settings.
On this same editor page you have the option to set an email to Active or Inactive.
Once you have a custom email configured, you'll be able to see it in an admin archive page. If you hover over an item you'll reveal a link to send a test email.
This plugin adds an option to disable the default receipt email.  It's under Downloads -> Settings -> Extensions.
This works fine if you have a custom email for each product, so that every product gets a receipt. That said, if you have many products with a custom email for each one, the purchaser will get a deluge of emails with a purchase.
You'll want to be careful to come up with a good strategy for this scenario.

Common Issues and FAQ

Product Variations

This extension does not support sending unique emails for product variations at this time.

Original Purchase Receipts

Easy Digital Downloads normally sends a purchase receipt. When Per Product Emails is active on a specific Download, that original email is NOT sent, only your custom email specific to that download is sent.