Anyways is the slang version of anyway and should never be used in formal writing. In fact, your English teacher will circle it in red pen and take points off if you use it. Adverbs can never be plural, so the "s" at the end is incorrect.
If you're writing dialogue, using anyways might sound more realistic in a younger character. But it's not standard and will always sound casual or colloquial whenever you use it.
Typically, you'll want to use anyway.
Be confident about grammar
Check every email, essay, or story for grammar mistakes. Fix them before you press send.
