Clarity does not support sharing documents or screens from within our application. This was done intentionally to keep things focused on quick, direct communication, without a need to consider location or available technology. In other words - we wanted to keep it simple.
As an option, if you want to send each other documents ahead of a call or must share your emails with each other, share a Dropbox link or use services like https://www.getcloudapp.com/
However, if you would benefit from sharing your screen during your call, we recommend join.me. It doesn't require an account to start a meeting and it's easy to share your meeting URL or meeting code during the call. The person viewing your screen only needs to have flash installed (very common).
Note that we recommend letting the other party know about this arrangement ahead of time so that they can prepare and be in the right environment.