EndNote is a reference management software with features for:
There is a free version -- EndNote Online/Web/Basic -- and a paid desktop version -- EndNote X9 or EndNote 20. Desktop users also get an EndNote Online account for sharing and collaborating.
Storage: 2GB or 50,000 references. Citation styles: 21.
Storage: unlimited. Citation styles: unlimited.
CWYW will automatically install with your purchase of EndNote Desktop. From the web, you can install the CWYW plugin by going to Downloads > Cite While You Write.
Visit the Apple app store to download EndNote for iOS.