Spaces is an application designed specifically for group sharing and planning. Read more about Spaces  

If you’re trying to put together a trip with your friends or family, you will need Spaces to put everything together. Sending plans, saving links, or simply talking with the other users in the group is easy and everything in the apps is built around this functionality.
The Spaces application is not all that friendly or even familiar because it tries to do something that hasn’t been done until now. Also, since it’s a collaborative tool, it also requires for people to work together. It comes with support for other services such as Google Search, Chrome, Photos, and YouTube.
Everything just works inside the app, whether it’s just a link or an attached picture.