To customize the Footer area, navigate to Appearance->Customize->Footer.
The Layout section allows you to set the number widget columns to be displayed in the footer.
The Style section allows you to change the background and text color of the footer.
The Content section contains two text fields where you can add text or HTML that appears at the very bottom of the footer. This is typically where you would want to place your copyright info.
In the Layout section, you can enable Footer Reveal. This allows the footer section to be revealed as the user scrolls down the page. You can also enable it on specific pages from the Footer Options box on the edit screen of any page.