You must activate voice features before you start building voice bots.
To activate voice features:
Log into Conversational Cloud.
Select Manage > Management Console from the hamburger menu. The Management Console appears.
Search for Voice bots in the search bar. The Voice Bots page appears.
Click the Click to activate option.
Scroll down, and in the pop-up window, enter your email address. Then review the terms and conditions, and check the box to indicate that you’ve done so. Click Agree.
Voice Features are now activated. You can go ahead and create and deploy voice bots.