“Reach” has several meanings depending on the context. Perhaps you should ask this question again, but also specify in which context you have encountered the phrases you mention. Are you talking about “reach me” in the meaning “make contact with me by telephone or other means”? For instance: "You can reach me at/on …(email address/phone number)" In that case, “You can reach me out at/on” seems rather non-standard to me. I have never encountered this usage except just now when I googled it.

Hello, Nadia. Thanks for your question. I will let someone else explain it to you, but I will say that "You can reach out to me" is an idiomatic expression that signifies one can can initiate contact or call another person. It also can have a more literal meaning as in "touch me," to make physical contact with someone if they are reaching to give you something (as in a physical object). I would add this: be careful with "me" in the second sentence. "Me" is the object of prepositional phrase. In this case it is confusing to have "me' after the verb when you are saying "reach out."