Abstract: A flat mailing envelope form for encapsulating an insert by an automated paper folding machine, includes a rectangular front panel with a seal flap fold edge, a bottom fold edge opposite the seal flap fold edge, a first side fold edge, and a second side fold edge opposite the first side edge. A back panel extends from the front panel bottom fold edge includes a back panel seal cohesive region, a first wing cohesive region, and a second wing cohesive region. A seal flap extends from the front panel seal flap fold edge includes a seal flap cohesive region configured to mate with the back panel seal cohesive region. First and second wings with cohesive regions extend from the front panel.