What's URL Encoding?
URL Encoding, also known Percent Encoding,
is an encoding of characters in a URL by replacing them with one or more character triplets that consist of the percent character "%" followed by two hexadecimal digits. The two hexadecimal digits of the triplet(s) represent the numeric value of the replaced character. This is important as URLs often contain characters outside the ASCII set, the URL has to be converted into a valid ASCII format.
In short, URL encoding replaces unsafe characters (characters outside the ASCII set) with a "%" followed by two hexadecimal digits.