To get your web page onto the internet, you'll need web hosting.
Web hosts are computers that are hooked up to the internet 24/7. These computers are called servers and they are assigned IP numbers in order that they may be found by other computers hooked up to the internet. It is on these servers that all your web files are stored.
Basically what happens is when you type a web address into the address bar of your browser and then hit Go, your browser sends out a request to 'get' that web page. The request travels across the internet to the appropriate web server and attempts to locate the web page on that server. If the request is successful (web page exists) then that web page will load (or download) into your web browser.