I personally, believe that having Tags would benefit iOS well. Say you have a picture on your iOS device that you would like to keep track of, or you save a document on your phone, etc. It would be really nice to have Tags like in Mavericks.
I think Tags will go between iOS and Yosemite, so if you Tag something in iCloud on Yosemite, it will show up on iOS. Unless you're specifically asking about Tagging a document in iOS, that I'm not sure about.
I think Tags will go between iOS and Yosemite, so if you Tag something in iCloud on Yosemite, it will show up on iOS. Unless you're specifically asking about Tagging a document in iOS, that I'm not sure about.