You can manually add new contacts to Yahoo Mail by using the Add a new contact feature in the Contacts tab or hovering over the recipient's name.
Transfer Yahoo Email to Gmail - The Hassle-Free Way
How To Create a Yahoo Account or Email Address Without a Phone Number
Yahoo Mail Forwarding: The Best Ways To Forward Your Emails
How To Add Contacts To Yahoo Mail (Quick and Easy)
Top 4 Ways to Backup Yahoo Mail to Computer
Import Excel Contacts to Yahoo Mail Account - Transfer XLS files to Yahoo
How to add contacts in Yahoo ?
How to Find Someone's Yahoo Mail Address - Howcast, email yahoo
The Best Way to Send Email to Multiple Recipients Today
How to Find Someone's Yahoo Mail Address - Howcast, email yahoo