it is better to include it in a <small>
tag
The HTML <small>
tag is used for specifying small print.
Small print (also referred to as "fine print" or "mouseprint") usually refers to the part of a document that contains disclaimers, caveats, or legal restrictions, such as copyrights. And this tag is supported in all major browsers.
<footer>
<small>© Copyright 2058, Example Corporation</small>
</footer>