Does iMac Mail Junk folder do the same as Spam folders on other venues?

Spam emails from hacks of phone company and/or internet provider

Last Monday, Mar 4 my phone company allowed a change of email address and took over my phone. I realized it on Mar 5th; My email address was taken and multiple companies now spam my two email addresses with the internet company. While dealing with my identity thief, I found that if you use spam key and then delete that the email (without opening) that the information goes to someone that keeps track and from then on... who knows.

But my iMac only has a Junk folder; so does the junk folder do the same thing as spam on other venues? I'm currently just deleting without opening the email of all addresses/companies etc I do not recognize .

Any Apple Wisdom would be greatly appreciated !?!

[Re-Titled by Moderator]