Log into your account. Look in the uppermost left-hand corner of your screen. You will see your User ID. If you have Activated Collaboration and created a Sharing Nickname it will be displayed along side it:
Hi YourUserID | SomethingElse
That SomethingElse is the Sharing Nickname you chose. If you don't see it there, you will need to Activate Collaboration and create one before sharing passwords with other users. Here's how.