I've just migrated my Classic catalog to CC and was trying to send some images to Flickr however I could only find the "Send to Facebook" option on the desktop version. Where is the "Send To Flickr" option in CC?
It's not there. The new CC app is a brand new app, so it will currently be missing many of the features you've been using in Classic. Obviously additional features will be added, but to help with prioritizing, it would be worth adding as a feature request at Lightroom CC | Photoshop Family Customer Community