ISO 21047 specifies the International Standard Text Code (ISTC) which is applicable to any textual work, whenever there is an intention to produce such a textual work in the form of one or more manifestations. It provides an identification data element for applications that record and exchange information about textual works and related manifestations. For example, the ISTC can be used for the purposes of collocating subsequent manifestations of the same textual work or derivations of the same textual work in applications involving electronic rights administration or information retrieval.

The ISTC is not applicable to manifestations of a textual work, including any physical products (e.g. a printed article) or electronic formats (e.g. an electronic book). Manifestations of textual works are the subject of separate identification systems.