To make a customer, partner or member contact a community user:
Go to the Contacts tab and click on the contact record of the customer or partner you wish to enable as a portal user.
Click on Community Option button and select Enable as Portal User.
Fill in the details of the user including their Username. Ensure their Email is correct. This is the email address where they will receive further instructions on setting up their account.
Click Save when you are done.
To edit this newly enabled user, return to the Setup Home page and go to Security > Manage Users.
Use the search bar to locate the user.