Yes, you can use WordPress themes on your own website. WordPress is a free and open source content management system (CMS) that enables you to create a website or blog from scratch, or to improve an existing website. WordPress themes are available from the WordPress Theme repository on the WordPress.org website.
You can also find themes on third-party websites and on the WordPress Theme repository. After you find a theme that you like, you can install it using the WordPress Theme Installer plugin. Then, you can configure the theme using the WordPress Theme Customizer plugin.