Well-formed document - Wikipedia
en.wikipedia.org › wiki › Well-formed_documentA valid XML document is defined in the XML specification as a well-formed XML document which also conforms to the rules of a Document Type Definition (DTD). According to JavaCommerce.com XML tutorial, "Well formed XML documents simply markup pages with descriptive tags. You don't need to describe or explain what these tags mean.
XML - Wikipedia
https://en.wikipedia.org/wiki/XMLThe material in this section is based on the XML Specification. This is not an exhaustive list of all the constructs that appear in XML; it provides an introduction to the key constructs most often encountered in day-to-day use. Character An XML document is a string of characters. Almost every legal Unicode character may appear i…