Text to speech (TTS) in web and Mobile app Bots

How to enable the Text to speech (TTS) capability for a Website or mobile app based bot in cloud version ? Does it require SSML tag to be configured ?
Found a document on Docs.yellow however it says contact support for enabling the feature. Text-to-Speech | yellow.ai

SSML need not be configured. You can customize by entering the required values within settings.

Please confirm this @Bhargavi_Chinnappa @akshay_bhat

This is a gated feature which has a cost associated to it. You can reach out on Slack for further discussion.