Choose the Segment or List you would like to export. Click on the gear icon next to the Segment or List and click "Actions" in the drop-down menu.
To export to Facebook, click the Facebook icon in the Actions modal.
Next, name your Export. Click "Configure Export."
The next screen will prepopulate the necessary information to import data to Facebook for advertising campaigns. You can select any additional data you would like to add in the export. Click "Export" to complete the export. The export CSV will include a Facebook ID as well as an email address. You can use either of these to import into Facebook to build an audience or an ad campaign.