There are various types of envelopes that are used to cater to the different needs of the business or personal work. One of the popular ones that are used widely is the open-ended envelopes. The placement of the flaps determines the type of envelope. In the open-end envelopes, they have the flaps placed on the shorter side of the envelope. For most of the other envelopes, the flap is generally on the longer side of the envelope. Such a type of design helps ensure that any content that you put inside be it normal or sensitive will not come out easily. When the recipient opens the envelopes it helps avoid any chance of papers falling out of them and thus ensuring safety.