The best way to adding custom fonts in Drupal is using the @fontyourface module.
The module will allow you to browse and apply web fonts (using CSS @font-face, supported in all popular browsers) from a variety of sources.
Use the following steps to Install @font-your-face:
Step 1: Place the extracted module in sites/all/modules/fontyourface
Step 2: Go to Administration » Modules and enable @font-your-face and one or more of the submodules.
Step 3: Go to Administration » Configuration » User interface » @font-your-face settings and import the fonts.