This feature helps to ensure that documents of a particular type are consistent in structure. Many industry standard DTDs have been created and used to facilitate information exchange between different organizations in the same industry. Because they are well formed, XML documents can be accessed by search engines, exchanged between different applications, and used to support transaction processing between different systems. Many different types of SGML and XML authoring tools are available. Some XML editors simply ensure that you create well-formed documents.
Some editors also provide publishing tools to facilitate the creation of style sheets.