It's a CMS (Content Management System), an online platform that allows you to create and manage a website.
Although it arose from the idea of functioning as a blog or news system, it's currently used for any website, whether presence, corporate, or web application, including electronic commerce thanks to the plugin WooCommerce.
It's surely the most used system, the one that gives life to the most web pages in the world.
Do you need help creating or improving your website?
Although I do not consider WordPress one of my specialties, the truth is that I know it and have touched it often (it is impossible to avoid it). In addition, I have really expert WordPress contributors who will be able to help if necessary.