This is a sample page. It is different from posts because it always stays in the same place and (with most themes) is displayed in the navigation. Most people start with an imprint or an "About Us" page with an introduction for possible visitors to the site. For example, it could say there:
Hi! By day I work as a bike courier, by night I'm an aspiring actor and this here is my website. I live in Berlin, have a big dog named Jack, like Piña Coladas but less being left out in the rain (without an umbrella).
...or something like:
Our company XYZ was founded in 1971 and since then has produced a lot of high quality ABC for the public. Based in Gotham City, XYZ now has over 2,000 employees and continues to develop great things for the entire Gotham community.
As a new WordPress user, you should go to the dashboard to delete this page and create a new page with your own content instead. Have fun!