The tabber is a crucial system to ensure that a mail piece is secure. Anything folded and not inserted into an envelope requires a tab for postal automation regulations. Obviously, postcards are not an issue, but virtually every other type of self-mailer, such as flyers, newsletters and many other forms of direct mailers, must be sealed through the use of a tab or glue seal so that they do not open and jam the high-speed sorter machines employed by the post office. Step Three: Another step in starting up a mail fulfillment operation is to obtain the appropriate folding and inserting equipment. There are several options available depending on a number of factors. Pick a vendor that can meet the unique needs of your specific operation. Considerations include: applications, volumes and frequency of mailings.