What is XML?
Extensible Markup Language (XML) lets you define and store data in a shareable manner. XML supports information exchange between computer systems such as websites, databases, and third-party applications. Predefined rules make it easy to transmit data as XML files over any network because the recipient can use those rules to read the data accurately and efficiently.

Why is XML important?
Extensible Markup Language (XML) is a markup language that provides rules to define any data. Unlike other programming languages, XML cannot perform computing operations by itself. Instead, any programming language or software can be implemented for structured data management.

For example, consider a text document with comments on it. The comments might give suggestions like these:

Make the title bold
This sentence is a header
This word is the author
Such comments improve the document’s usability without affecting its content. Similarly, XML uses markup symbols to provide more information about any data. Other software, like browsers and data processing applications, use this information to process structured data more efficiently.

XML tags
You use markup symbols, called tags in XML, to define data. For example, to represent data for a bookstore, you can create tags such as <book>, <title>, and <author>. Your XML document for a single book would have content like this:

<book>

<title> Learning Amazon Web Services </title>

<author> Mark Wilkins </author>

</book>

Tags bring sophisticated data coding to integrate information flows across different systems.

What are the benefits of using XML?
Support interbusiness transactions
When a company sells a good or service to another company, the two businesses need to exchange information like cost, specifications, and delivery schedules. With Extensible Markup Language (XML), they can share all the necessary information electronically and close complex deals automatically, without any human intervention. 

Maintain data integrity
XML lets you transfer data along with the data’s description, preventing the loss of data integrity. You can use this descriptive information to do the following:

Verify data accuracy
Automatically customize data presentation for different users
Store data consistently across multiple platforms 
Improve search efficiency
Computer programs like search engines can sort and categorize XML files more efficiently and precisely than other types of documents. For example, the word mark can be either a noun or a verb. Based on XML tags, search engines can accurately categorize mark for relevant search results. Thus, XML helps computers to interpret natural language more efficiently.

Design flexible applications
With XML, you can conveniently upgrade or modify your application design. Many technologies, especially newer ones, come with built-in XML support. They can automatically read and process XML data files so that you can make changes without having to reformat your entire database.