Several people have asked how to make an A2 envelope that holds a 5 1/2″ x 4 1/4″ card. By folding an A2 envelope differently you can make a pocket envelope.
First cut your paper at 6 3/4″ x 10 3/4″
Then score 1/2″ on each side as shown below
Score at 3″ and at 7 1/2″ as show below
Cut the corners along the score lines as shown below
Corner round all corners if desired
One way you have a pocket envelope as shown
And folder the other way you have a standard A2 Envelope as shown