If you are an administrator, and provided the option has not been disabled (see Configuration), you can assign work or share work with a new contact by entering their name and email address. See Assignment and Share for details.
The contact will be sent an email to invite them to connect. When they follow the link from the email, they will be shown a start page that lets them sign in or create a new account.
If the contact does not already have an account, they can use Create account to create an account - see Sign up for details. Their account will automatically connect to yours and they will be sent the task that you have assigned or shared with them.
If the contact already has an account, then when they sign in a connection to your account will be created and they will be sent the task that you have assigned or shared with them. If they already have a connection to your account, that connection will be reused.
If multiple assignments or share requests are made for the same contact, only one invitation email will be sent.