Goals in Google Analytics are similar to conversions in AdWords, in that they can help you track specific behaviors on your website, such as sign ups or sales. If you already have a goal (or multiple goals) created in your Google Analytics account, you can import them into AdWords as conversions. This will enable you to see how your ad efforts relate to specific goals you already decided to track via Google Analytics, without needing to set up AdWords' conversion tracking and add an additional pixel to your website.
In order to be able to import Analytics' goals into your AdWords account, your AdWords and Google Analytics accounts will need to be linked first. You will need to enable auto tagging in AdWords, and be opted into data sharing settings in your Google Analytics account under the Account settings page in your Admin section. Finally, your AdWords ads will need to have resulted in a goal completion.