The correct contraction of "will not" is written as "won't." Like many other contractions, it is used in informal writings such as newspapers, fiction and instructions, explains the Goodwill Community Foundation. However, the contractions are grammatically incorrect for formal writing, such as in an academic paper.
The contraction "won't" has its basis in an older form of the word "will," because over time, the word changed, but the contraction remained the same, says the Goodwill Community Foundation. Using the contraction makes the writing simpler and easier to read. Everyday speech and informal writing also use the contraction won't. Contractions are used mainly with auxiliary verbs also with "be" and "have."
When using the contraction "won't" in a sentence, it is important to remember not to use two contractions in the same sentence, according to Cambridge Dictionaries Online. Being a negative contraction, "won't" can be used at the end of a clause. An example is, " No, I won't." The contraction is used commonly after a pronoun, such as in, "She won't come back."
Contractions such as "won't" are an important stylistic device, because they make writing seem friendly and accessible, reports YourDictionary. Another advantage is that they help to reflect how a character speaks, in a novel or play, and they also save space when writing. Other examples of informal writing that require contractions are advertisements and slogans.