Note the construction and terms used for envelope design and machine inserting when creating specifications for printing.

• Flaps more than 2" long or too pointy don't allow for machine inserting and will cost you more if hand insertion is needed.
• Side seam construction can sometimes save you money!  Diagonal seam is shown here. 
• Windows come in many sizes and positions and depend on how large an address area you require.
• Many envelope colors are available "in stock."
• Clear, glassine, brown kraft and many other interesting stocks make a BIG impact!