For text on a website, the fonts are limited to what the “rest of the world” has on their computers. For the most part, they are broken down into these font families, I’ll put each name into its own font family:

Arial, Helvetica, sans-serif
Times New Roman, Times, serif
Courier New, Courier, mono
Georgia, ‘Times New Roman’, Times, serif
Verdana, Arial, Helvetica, sans-serif
Geneva, Arial, Helvetica, sans-serif

If you want to get fancy and use other fonts, you’ll need to use Photoshop or a fancy plugin like Headline Images.