This article will explain how you can add external participants to a task in 123-mail.
Log in to your 123-mail account. Enter your username and password into the boxes provided, then click the Login button.
From the toolbar at the top of the page, click the Tasks button.
Click the New task button at the top of the page.
Insert the task information; including subject, due date and priority.
Click on the Add participant button.
Enter the Name and E-Mail address of the person you wish to add. Then click the Add button. When you have added all the participants you require, click OK.
Finally, click the Save button.
The participants you have added to your task will receive a notification stating that they have been added to the task, and will be able to see all of the details you have sent them.