This is an example page. It differs from posts in that it always stays in the same place and (with most themes) is displayed in the website navigation. Most start with a legal notice, privacy policy or an “about us” page to introduce themselves to potential website visitors. For example, it might say:

Hello! By day I work as a bicycle courier, by night I’m an aspiring actor and this is my website. I live in Berlin, have a big dog called Jack, like piña coladas, but I don’t like (without an umbrella) being caught in the rain.

…or something like this:

The XYZ company was founded in 1971 and has been providing the public with high quality products ever since. At its location in a small metropolis, the company employs over 2,000 people and supports city dwellers in many ways.

As a new WordPress user, you should go to your dashboard to delete this page and create new pages and posts for your site. Have fun!