WordPress has two versions: hosted and self-hosted. Serious writers recommend self-hosting. But beginners can opt for the hosted version. Here is a basic introduction to WordPress:
The hosted version of WordPress (WordPress.com) is easy to learn and use. It also has minimal features. The self-hosted version of WordPress (WordPress.org) is highly flexible and rich in features. It has a steeper learning curve.
Like most people, I recommend that anyone serious about blogging use the self-hosted version, WordPress.org, and bypass the hosted version of WordPress, WordPress.com.
However, for a person not sure about blogging and interested in just trying it out, WordPress.com can accomplish that nicely and with minimal fuss and cost.
Moving content from WordPress.com to WordPress.org is not hard—for someone who has done it before. It does take a bit of effort, but transferring posts is mostly following a set of instructions. There are a lot of instructions online and this guide looks good.
However you proceed, I wish you the best. Happy blogging!