Copyright is a big issue for anyone putting content out into the world. While nothing works to protect you 100% from those who have no qualm in stealing, it's definitely important to cover your bases as much as possible.
Something you might not know - a copyright notice is not legally required for protection to be legitimate. Copyright automatically applies to original works (which includes websites). That being said, it's always best practice to include a notice as this can help if you find yourself actually having to defend yourself in court against someone who's stolen content from you.
The most basic form of the notice would look like this:
Copyright © 2001 Business Name
Technically, including both the word "copyright" and the © symbol would be redundant, but it's fairly common to use both. The year displayed is the year of publication, but NOT the year for which protection is current. In other words, this year does not need to be updated constantly on your website. However, you can use a year range if your content is updated regularly, in which case you might want something like:
Copyright © 2001-2022 Business Name
The last part is the name of the person or business to whom the copyright belongs. (You don't need to include the word "by".)
If your website content includes bits that are actually covered under the copyright of others (used by their permission) you may want to include clarification in your notice. For example, if you are reselling the Mailchimp marketing service, and have included their logo and some materials on a page on your site, you may want to use a notice that looks something like this:
Copyright © 2001-2022 Business Name Mailchimp™ is a registered trademark of the Rocket Science Group.
You can also include the phrase "all rights reserved" or "some rights reserved" to further clarify your copyright position. Though if you used the later, you'd want to include some details somewhere that outline exactly which rights are reserved, and what people are allowed to use and how.
For use on a website, a copyright notice is typically included in the site footer, visible on every page within the website. If you need to outline anything beyond a sentence or two, you can include a link in the footer to a separate page.
If you want to learn more about copyright, here are some additional resources:
April 21, 2022 in Articles.