What are HEX codes

Answer 1

Hexcodes are 6 digit numbers starting with a hashtag(#) and used to specify a color.This is an example of using a hexcode in css...

body {
background-color:#000000 /*This color is black.You can also use #000*/
}

Answer 2

Source: Wikipedia:Web colors are colors used in displaying web pages, and the methods for describing and specifying those colors. Colors may be specified as an RGB triplet or in hexadecimal format (a hex triplet). They may also be specified according to their common English names in some cases. a color tool or other graphics software is used to generate color values. In some uses, hexadecimal color codes are specified with notation using a leading number sign (#).[1][2] A color is specified according to the intensity of its red, green and blue components, each represented by eight bits. Thus, there are 24 bits used to specify a web color, and 16,777,216 colors that may be so specified.Source:Wikipedia