It was not mentioned during the announcement of the service, but the folks at Re/code confirmed it when Apple released a statement to them. “As an Apple Music member you can add anything from the Apple Music library — a song, an album or a video — to your collection, and that’s just the warm-up act. From there you can create the perfect playlist from anything you’ve added. You can save it for offline listening and take it on the road.”
This is particularly handy especially since this is a streaming platform, but given that sometimes we want to conserve data, battery, or don’t have access to the internet, having an offline mode makes sense although users would probably need to prepare for this in advance as the songs will need to be downloaded and saved first.
Apple Music is currently pegged for a release come 30th of June and will require iOS users to run iOS 8.4 at the very least. It is pegged at $10 a month for individual users, and $15 a month as a family plan that can support as many as 6 users.