Clicking on the menu item “Footers” of the main admin navigation you will see all the available footers.
You can edit them or add a new one exactly as you do with a normal page or post.
In the Footer editing page you can set whatever you want, change the layout and content using the page builder. You have no limits to the customization.
Usually you need to edit the footer to add your copyright and custom links.
In the following video you can see an example of what you can do in your footer.