Need to access your invoice? Simply log into your account on Adafruit.com by using the sign in button on the upper right hand corner of the site.
If you are already signed in just click on "My Account".
Now click on "Order History"
Here you will see a list of all the orders you made under your account. Go to the order you want an invoice for and click on "Invoice".
That's it! You can print out the invoice or come back to it at anytime.