There are three distinct types of rubber stamps: traditional, where the pad is in a separate container from the stamp; Self-inking stamps, which have a self-contained die that rests against the pad until the die is flipped 180 degrees to make an imprint; and pre-inked stamps, where the die itself is actually impregnated with the ink.
Rubber stamps for business commonly show an address and corporate logo. They often have movable parts that allow the user to adjust the date or the wording of the stamp. They are used to date incoming mail, as well as to denote special handling for documents. In some countries it is common practice for formal documents such as contracts to be rubber-stamped over the signature as additional evidence of authenticity.