This is an example page. It differs from posts because it always stays in the same place and (in most themes) is displayed in the website navigation. Most people start with an imprint, privacy policy, or "About us" page to introduce themselves to potential visitors to the website. For example, it could say:
Hello! During the day, I work as a bicycle courier, at night I am an aspiring actor, and this is my website. I live in Berlin, have a big dog named Jack, like piña coladas, but less so being left standing in the rain (without an umbrella).
... or something like:
XYZ was founded in 1971 and has been providing the public with high-quality products ever since. Located in a small city, the company employs over 2,000 people and supports the city's residents in many ways.
As a new WordPress user, you should visit your dashboard to delete this page and create new pages and posts for your website. Have fun!