Before a domain name can be considered "yours", it must be registered.
This must be done through an accredited Registrar and incurs a registration fee.
There are a large number of domain name registrars and they are controlled by ICANN, the Internet Corporation for Assigned Names and Numbers.
ICANN is a non-profit organization that ensures that all the registrars access common databases so that, for example a given domain name can only be registered once and can have only one owner.
Individual registrars set their own price levels and conditions and are in competition with one another.
The system works well.
You must register, pay for and own a domain name before you can build a website on it.
I recommend Namecheap as your domain name registrar. Their pricing is competitive, their support is excellent and their website is easy to navigate.
Here's how to register a domain name with Namecheap:
Click on Namecheap and enter the domain name you wish to register.

Enter the domain name and click the Search button.

As I've already registered goldilockssoffee.com, Namecheap is reporting that it's not available and showing me other alternatives with different extensions.
But, remember, we are only interested in dot com domain names.
I'll be using goldilockscoffee.com as a case study throughout this course and I'll be encouraging you to register your own domain and build your own website on your own domain, so the next screens are just to show you how to do that. You'll be able to refer back to this lesson when you are ready to proceed.
Let's see what happens when we enter a domain name that IS available.

Now I don't wish to register redridinghoodcoffee.com but let's proceed as if I were going to.
Click the Add to Cart button.

Note that you are being offered a heap of additional facilities under the heading "frequently bought together".
YOU DO NOT NEED ANY OF THESE.
Just click the Checkout button.

You do not need to change anything on this screen (unless you want to turn auto-renew on) so just click the Confirm Order button.
Then go through the process of creating a Namecheap account and pay for your new domain name by credit or debit card or PayPal.
For future domain name purchases, you will be able to login to your account using the username and password you created.
Outcomes
At the end of this lesson, you should have registered your chosen domain name with Namecheap and feel that you are making real progress.
Click on the image above for the e-book How to Register a Domain Name