How to choose envelopes and sleeves?

If there exists a large diversity in the envelopes and the administrative envelopes, it is because they respond each to a well-defined use. You will not use the same (administrative) envelope for sending, for example, an invitation, an invoice or a fragile object. But it is not always easy to know which size, material, grammage or closing system will be the best for your mail. In order to help you to find the correct type, we will give you some tips here.