An XML document consists of a sequence of human-readable characters, with no special additional codes or binary data. The characters < and > are used to mark the start and end of tags within this sequence. A tag may be a start-tag (such as <p>) or an end-tag (such as </p>). A tag always begins with a name (doc, p, placeName in the above example) and may also contain attribute specifications (such as n=”1″). The purpose of a start-tag is to mark the point in the sequence of characters at which some element, of a type indicated by the tag name, starts, and the purpose of an end-tag is to mark where that element ends.
Tags Codes or labels embedded within a string of characters to indicate the beginning or end of an element.