How do I change the footer of my site?

I'm using the "Product" theme, but I have a feeling that the answer to this question would apply to more than just this theme - I am trying to change what it says at the footer of my site. Right now, it just has the copyright year and a "back to top" button. I'd like to add things like Contact, Affiliates, etc. down there, but I just can't figure out how to change it without going into the footer.php file and changing it manually. I'm trying to avoid doing that, since the changes would get overwritten every time an update came out for the theme.
Thanks in advance.