HTML is a markup language used to provide structure and style to web pages and web applications. Understanding HTML tags and how to put them together makes designing a website easier.
XML is a markup language and file format for storing, transmitting, and reassembling arbitrary data. XML allows us to use elements and develop customized markup language.
HTML has predefined tags which can be used to create web pages, whereas XML allows users to define their own tags, and they can use them in any language they choose.