The phrase url encoding refers to the process of converting URLs and other text strings into a format that can be submitted in a web browser. When rendered, the coded URL will look like gibberish and is often hard to read.
The process of encoding a URL or an email address by using the hexadecimal equivalents of the alphabet is called URL encoding or percent-encoding. A URL could be encoded as http%3A//www.nytimes.com, and an email address could be encoded as charles%40example.com. Percent-encoding exists because it's difficult to read the mathematics behind characters such as ":" or "@", if they were not encoded.