If you plan to create a website for your business you will need to register a domain name and use some server where will be the domain hosted. Since most websites do not need the whole server, you can save a lot of money by using a web hosting service. Web hosting companies host multiple websites on a single server so they can offer better price comparing with running your own server.
Domain name is an unique address of your website, something like yourdomain.com. You can register a domain with some international extension like .com, .org, .info or with some national extension like .ca, .us or co.uk.
There are two ways how to order a domain name:
You can register it with some domain name registrar like GoDaddy or NameCheap. You will get access to an online account where you can set up the DNS servers. Domain names usually cost about $10 a year or less.
You can also let your web hosting company register the domain for you. When you order a hosting plan from some web hosting company like MarbleHost.com you have the option to buy the domain together with the hosting plan. If you use this way, you will not need to make any domain related settings, the hosting company will set up everything for you. Quality web hosting package usually cost between $5 and $10 per month.
You will receive a welcome email with some important information:
1. How to access web hosting control panel.
2. How to upload files to the server.
3. Pop3 settings which are needed to download your emails.
Now log in your web hosting control panel. Set up at least one email account, something like firstname.lastname@example.org. Use the pop3 settings from the welcome email to access your emails using your email client. If you have not installed one I recommend to use ThunderBird -- it is freeware with many great features. Now use some FTP manager to upload the files to the server. As soon as you finish these steps your website will be accessible to anyone.