Question with a million answers but it’s simple really.

Ingenious actually.

With tiny bit of what’s called HTML or Hyper Text Markup Language you can make a webpage!

For instance here are three simplest examples:

  • To make text look bold the HTML is: <b>text</b>
  • To make text look underlined the HTML is: <u>text</u>
  • To make text look italic the HTML is: <i>text</i>
then finally you open that file up with a browser and voila!  You get:

texttexttext

the full code is this:
<html>
<body>
  <b>text</b>
  <u>text</u>
  <i>text</i>
</body>
</html>
So if you copy paste the above HTML code into a notepad and save it as: text.html      Then doubleclick on the saved file should open up a browser and show you your newly created work!
Needless to say, that’s only the tip of the iceberg…probably less than <0.001% of what needs to be covered however, no harm in experimenting.   Plenty of tutorials around the web.
Check them out!