You can add as many users to your account as you want. Users that work with you in Ofuz are called co-workers. Its a general term for everybody you are working with. From your office co-workers to your vendors and customers.

To add co-workers to your account:

Sign in your Ofuz Account,
click on the Co-worker link on the top right.
Search for your co-worker by first-name or last-name.
If your co-worker is not in Ofuz you can send him an invite to join and become your co-worker.

Once your co-worker as approved your request you will see him in your list of co-worker and add him to your projects or share contact with him.