Hello to all.

I don't know really where to put this question, but what I am wondering is how do I register a slogan so that no one else can use it word for word?

Like you see wendys has "old fashioned hamburgers" and it has the R or TM with the circle around it.

I would just like to keep my slogan mine and don't know how to do it.

Thanks

You have to register the slogan as a Trademark. It is a legal process and takes a while to complete it. If you're in the US, you can get started here:
Trademark Electronic Application System (TEAS) Home Page

Trademarks - where to start