I often see people having html buttons for links in stack overflow?
how do I visually show a button on stack overflow
<button><a href="www.jsfiddle.com">link to fiddle</a></button>
Are you referring to this Click here?
<kbd>[TEXT HERE](URL HERE)</kbd>
However as recommended by animuson in a comment to your post, if you are intending to use this for links in a post, avoid doing so as it can be ambiguous to a user. The tag is to be used to showcase user input. Users may not be aware that it is a clickable button. try to always use the
[TEXT](URL) tool to provide a hyperlink for the user.