A domain name is the bit of the URL (the site address in your browser’s search bar) that identifies a web page — in this case your website. For example, ours is websitebuilderexpert.com. You can register them separately at sites like GoDaddy and Domain.com, but website builders offer to do it for you when you sign up with them. Most provide it for free (at least initially), while a handful charge a few extra bucks.
Your website needs a place to live on the web, and the quickest way to reserve your web address is to find a web host. There are a variety of cheap web hosting providers, and each one has a specialty. Look for a web host that offers a price that fits your budget, has the web tools you need to create your envisioned website, and provides support when you need help or have problems.