"Anyone" or "Any One" Differences

Hi there,  GoldenGlowVibes . Both you and your friend are correct.

 "Anyone" is a single-word pronoun that refers to any person, while "any one" is a two-word phrase that refers to a single person or thing.

For example:

"Can anyone answer this question on the board?" the teacher asked.

(The teacher is asking one of the students to answer the question but she's not asking a particular student.)

Any one of these microphones is working so just pick one and go to the stage already.

('Any one' is usually followed by the preposition "of".)