Envelope: dimensions of the envelope are usually proportionate to those of the letterhead (A4). The dimensions of the closed envelope would better be one third the height of the letterhead plus six millimeters (in width and height).
Address, telephone number, name, logo of the company, fax, website, and email address are the necessary items on the envelope. In fact, text is considered to attract the audience’s eyes. The logo and the title are usually located on the top left. The elements are mostly laid out in landscape orientation.
It should be noted that an empty space should be left on top right of the envelope for attaching postage stamp and postal service operations but if the postage costs are already paid for in advance, this part could be used as well. Leaving this space blank means not to insert text or images such as the logo, but using ornamental curves or lines and decorations is allowed.
An important point in the design of office paper set is the necessity of visual harmony in all products. In other words a specific identity should exist in letterheads, business cards, envelopes, personnel cards … This common visual identity can be formed by presenting common decorative visual elements, through a coloring scheme, or a similar layout … Usually the starting point for the design of office paper set is the letterhead or the business card, and then, based on the initial pattern, other items are conceived. Changes or revisions on the already completed works are possible at any stage.