Using Plugins with Ardour
Ardour does not come with any built-in signal processors of its own. However, there are hundreds of plugins (effects and instruments) that you can use with Ardour, many of which are available at no charge.
For information on how to use plugins with Ardour, please see the relevant section of the manual which also provides some information on getting plugins too.
We also have a guide to software synthesizers ("instruments") for use with Ardour 3.