Above the tool:
Fill in your name and year, and the generator builds a complete copyright notice — both the display text and the HTML to paste into your footer.
Below the tool:
What makes a notice valid? Three elements: the © (or the word “Copyright”), the year of first publication, and the owner’s name. Everything else — “All rights reserved,” license lines — is optional emphasis. The notice doesn’t create your copyright (that exists automatically), but it eliminates any claim that someone didn’t know the work was protected.
Which year? The year the site launched, or a range from launch to now if it’s continuously updated. A dated year isn’t a legal problem, but it makes a site look abandoned — the auto-updating snippet fixes that permanently.
Where does it go? The footer, on every page. Users, courts, and other publishers all expect it there.