1. Digital Engagement license is required to use this feature.
2. SMS Channel should be setup in the org. Follow https://www.infallibletechie.com/2020/04/sms-channel-setup-in-digital-engagement.html for setting up.
Follow the below steps to send Mass or Bulk SMS Messages from List View.
1. Make sure the user have “Send One-to-Many Messages” Permission.
2. Open a List View.
3. Select the records.
4. Click Send Message button.