Sharing a project or playlist is a great tool when there are several people involved in choosing music for your productions.
To share your project or playlist, you will need to ensure the playlist is not set to private.
If a playlist is private, you will need to make a copy of the playlist by clicking on project options and click on copy.
Rename the copy and click ok to create a public shareable version of the playlist.
Once the playlist is public, if you are premium user you will be able to see a share and collaborate button as seen in the screenshot:
Just hit the "share and collaborate button" and type in the email-address of the person you want to share your project or playlist with.
Please note: Anyone that has access to your shared playlist or project can add and delete songs.