Stamp
From OpenKM Documentation
Stamp is only allowed in taxonomy view for any document which can be converted to pdf or be a pdf. In order to stamp a document is necessary got configured open office service, consider take a look at OpenOffice.org or Application_configuration.
Detail of the functions according to their icons:
Stamping a document
Fist must select a document ( convertible to pdf or pdf ) in taxonomy view, then click the stamp icon. It'll appear a popup.
Several stamp types can be assigned in administration view to each user. User must select one of the available stamp he's got and execute it. After some time it'll be generated a new pdf file ( or new version pdf file in case the selected stamped file was a pdf ).