Note: This is for blogs using the old classic Blogger template. For those using the New Blogger template, refer to Putting a copyright notice that automatically update. You may also be interested in What to do when your blog content is copied and how to discourage copying.
In practice, copyright notices are normally placed at the footer. Most Blogger standard template default footer put in placed at the footer to make it convenient for a blogger to just edit it, but have been commented out so that it is invisible. In your template, look at the bottom of the page for this block of HTML:
. All rights reserved. (Note: the special HTML for copyright HTML code is actually an image of the special HTML character, and you will have to manually type it in rather than just a copy-paste operation).
Note: If you have any problem with the codes, please put your comment in the comments section below.