Print the free files onto card stock. Click here for: lily | daffodil | collage 

Once printed, trace the outline of your envelope on the backside of the printed card stock. 

Mark new lines 1/4" in from the original lines. This is easiest to describe in picture form, see below (click to enlarge). 

Cut the shape out, and place the liner inside of the envelope to double check that the sizing is correct. Trim off any necessary pieces. 

Add a bit of glue to the backside of the liner, and secure it into place on the inside of the envelope. 

Use a scoreboard to score a line down the fold of the top of the envelope. Enjoy!