Hi there!
In any kind of formal writing, the writer should be sure to use a formal language.
Using a formal language, not using slang or including swear words, is a crucial part of being a formal writer. A formal piece of writing also needs proper formatting, layouts, punctuation, grammar (and all that good stuff you learned in your early days).
Not only does this make your piece look more professional, it attracts the audience and gains trust from them.
Hope this helps!
