Three things need to be working for you to be able to use websites on your computer as if they were on the internet (the internet includes your computer, but that’s another story).
Apache – this is a program that ‘serves’ websites to internet browsers (Internet Explorer, Edge, Firefox, Safari, Chrome, Opera, etc.). There are other programs that do this but apache is currently the most popular
Virtual Hosts – the setup information for websites other than the default one that Apache creates when it is installed. For instance, you might want to create a website on your computer where you can test WordPress called wordpress.local (this is the example I’m going to use for the rest of this, and any other, posts).
DNS – the Domain Name Service – translates domain names (which are easy to remember) into IP addresses (which are not). This allows you to remember domain names (like: wordpress.local) and not to have to remember IP addresses (like you remember the names of your friends in your phone but you don’t need to know their telephone number)