There are third-party themes available as well, but make sure they’re not infected with malware before you download them.
You can also search through the options from the Microsoft Store, which will give your entire computer interface a new look and feel. These are great if you want to change up your background to have a slightly different look than the standard Windows 10 theme. If you don't plan to go through the entire process of finding, downloading, and installing a new laptop or desktop theme, you’ll be happy to know there are many themes already available on the operating system.