In audio editing, there are two types of filters: generator and processing. Generator effects artificially create sounds using your audio track (or add it in). Processing effects work with the existing audio and change it to suit your needs. When you install Audacity, there are filters of both types that are already installed. You can also download additional filters, are called plug-ins, that allow you to do even more audio filtering. First, let's discuss a bit more about what filters are and how they can help you when editing audio tracks.
There are four types of effects, namely:
Virtual Studio Technology (VST) Plug-ins—These are what we call third-partly plug ins. They are not bundled with Audacity. You need to add these in after your initial Audacity installation. VST Plug-ins are for Windows or Macintosh computers only.