Technically WordPress is a Content Management System, or CMS, for all the digital files that make up your website.
Think of WordPress as the foundation for your website. It coordinates all the pages, blog posts, menus, and other files that make your website work. It is very flexible, and many types of websites can be built using WordPress.
WordPress is open source software, meaning its code is public and it is free to use. It is not owned by anyone or any company, so anyone can write additional applications and themes that work with it. Anyone can download WordPress from wordpress.org.
Remember, you can’t build a website with WordPress alone. You will also need a theme, plugins, and website hosting. You will have to pay for some of these things.