With the Broadcast List feature you can send a message to several of your friends at once.
Broadcast Lists are saved lists of message recipients you can repeatedly send broadcast messages to, without having to select them each time.
To create a Broadcast List:
This will create a new Broadcast List. When you send a message to the Broadcast List, it will send to all recipients in the list as a normal message. When they reply, it will appear as a normal message in your chats screen; their reply will not be sent to other recipients in the Broadcast List.
Note: Only contacts who have added you to their phone's address book will receive your broadcast message. If your contacts are not getting your broadcast messages, please make sure they have added you to their address book. Broadcast Lists are a one-to-many communication. If you want your recipients to participate in a group conversation, you should create a Group Chat instead.
In the BROADCAST LIST info screen you can:
Learn how to use Broadcast List feature on: Android | iPhone | Nokia S40 | BlackBerry | Nokia S60 | BlackBerry 10
Cheers,
WhatsApp Support Team