These two words are pronouns that are used to refer to something. They bear a resemblance to each other in spelling and sound, yet they are two different words and meanings. The word everything relates to all things, and all seen or unseen, are part of everything; however, even nothing is a part of everything. When you deliver a message through conversation or writing, you use everything to refer to all things that are crucial about the subject. There is no limit to everything.
Anything, on the other hand, is used to denote any of the items that are about the subject matter. It refers to any portion of a whole thing, whole object, or entire idea. It can be either one, all, or some of the quantity or extent of a thing. Also, they refer to different things, and in phrases and sentences, they are used in different contexts.