This template is for a box base that's shaped like an envelope. (Note that it does not include the template for the panel of words that I used to secure the top flap of the envelope box...)
The template comes with two parts: Envelope Box 0001 - Part A, Envelope Box 0001 - Part B
I also included instructions on how to ensemble the 2 pieces (part A and part B) together.
The finished dimension of the box is as follows: 7.5" (width) x 9.375" (height) x 0.375" (depth)
Download link: Envelope Box Template