To send a feed out to a partner, you will need to first configure where it should be sent and the required settings.
From the setup screen, select Feed Deployments.
Select the Deployment Type where the feed should be sent.
Fill out all the applicable fields including Name, Status and the correct Account, Catalog and Feed.
Click Save. This will take you back to the feed status page. The feed will activate on the schedule provided or you can click on Deploy under Audit > Tasks to run the feed immediately.