What is XML?
Extensible markup language (XML) is all about describing the data. Below is a XML which describes an invoice data.
Shoes
12
100
10
An XML tag is not something predefined but it is something you have to define according to your requirements. For illustrate in the above example of invoice all tags are defined according to the business needs. The XML document is self describable; any one can easily understand looking at the XML data what exactly it means.