Have confidence when mailing out annual reports, brochures, and sales literature in our secure booklet envelopes. This envelope's open side style and side seams make it suitable for automatic insertion. Options such as peel and seal closures or square flaps make booklet envelopes extremely versatile. Choosing envelopes with or without windows allows you to choose how much information can be seen from your mailing. Shop from our wide selection of booklet envelope sizes and find the perfect fit for you and your business.