Answer:
Formal writing does not have slang, contractions, abbreviations or vague words (such as things or stuff) in it, and is usually used in any kind of essay. Informal writing is when using slang, abbreviations, contractions, and vague words is allowed.
Explanation:
An example of informal writing: (text message) "hey u want 2 go get pizza or something"
An example of formal writing: (informal narrative) "Rachel Carson was an author and a marine biologist and was best known for writing her book Silent Spring."