I'm running Win 10 Pro and the new PS 2018. I was delighted to see the Quick Share option but was quickly disappointed when I saw flickr wasn't listed. While I can see how to refresh this list on an Apple product, I'm using a windows machine. Surely, there's a way to add flickr to this list? Please?
Your operating system preferences determine the actual list of services appearing in the Share panel. You can tweak these preferences. For example, on Windows OS, add/remove services to the Share panel by tweaking System Preferences > Extensions > Share Menu. See How to quickly share files in Windows 10 - CNET for more information. These are the services that show up in the Quick share menu on a Windows.
You may refer this article Photoshop Help | Quickly share your creations for more info.