If you want to create a website or blog you will need to sign-up with a website hosting service. Through this service you will get space on a server, with a high speed internet connection, on which you can host your site.
In addition to a hosting service you will also need a domain name. You may be able to register a domain name through your website hosting service or they may include one in the package (but you don't have to use this if you really want, for example, a.com or.org).
However, although this is the easiest way to get started, it will probably not be the cheapest. You should look at several domain registration sites as prices do vary even for top level domains like.com. To link a domain name to your hosting account you simply have to enter your hosting company's nameservers on the domain registration site.
You will access your hosting service via a control panel the functions of which will include, setting up ftp accounts to access your server and upload files, creating and managing email accounts on your domain, managing databases, running backups and viewing site statistics.
There are a great many companies offering a website hosting service and it is not easy to select the right one for you. You might think that website hosting review sites would help but unfortunately these are numerous and of varying quality. It is, however, worth looking at independent forums like hostjury.com and webhostingtalk.com.
The best web host for you will be one that meets your needs at a reasonable price. Simply looking for the cheapest service is not a good idea, conversely you cannot assume that the most expensive will be the best. The key factors to consider are:
Loading Time - Pages must load fast otherwise your site will provide a poor user experience and they will not return.
Uptime - Look for an uptime guarantee of 99.9%, any downtime is bad as your site will simply not be available and you will lose visitors - maybe permanently.
Technical Support - If you experience urgent problems you want help immediately. You should therefore expect support to be available 24/7 by telephone, not just by email.
Disk space and bandwidth should not be an issue if you are just starting your site but do not be swayed by offers of an "unlimited" amount of these resources as this is meaningless. Most hosting accounts are "shared" which means that server and bandwidth are shared by multiple users. This is fine for most people but if your site might become very busy in the future look for an upgrade path to VPS (Virtual Private Server) hosting and then to Dedicated Server hosting.