color

Question

why do we have different colors to the tags

Answer 1

Are you referring to the syntax highlighting? It is for better readability and also makes it easier to find errors. The syntax highlighting is only for humans to read, it doesn't change the code in any way.
More information:
https://en.m.wikipedia.org/wiki/Syntax_highlighting

Answer 2

For Readability, Distinguishing Tags, Variables and keywords. Also to, find a syntax or typo.