Emily London Miller (Emily London Portraits) explains how to use Lightroom to format your prints with a border, so you can order 8×10 prints with a 7×10 image, and then slip those prints into an 11×14 mat with a 7×10 opening. Emily goes in depth and with great detail to describe all the logistical components that go into how and why to order the prints this way.
Related Products:
Slip-in Mats: available without a box purchase in packs of 10 or 25.
The Marilyn: an envelope shaped box to hold matted prints. Made in USA by Finao.
The Portfolio Box: traditional clamshell box to hold matted prints. Made in Australia by Seldex (available for purchase in North America through Finao).