Mail account. ”  You have the option to use Bcc, which will hide the e-mail addresses for every recipient’s privacy.  On the “To” field, you can type in your own e-mail address, as filling this field is required to be able to send a mass e-mail.
Log into your Yahoo! Click on “Compose. Click "Cc" on the right of the “To” line. Use Bcc. Type in the e-mail addresses of your desired recipients. Input an e-mail on the “To” line.