Twitch Integration for Ultimate Chicken Horse is only available on PC.
To enable the Twitch integration, open the Menu, and go to Twitch.
In the (channel name) field, type in the Twitch username for the channel, and press Enter. If the channel name is valid and Twitch Voting is set to On, you will see some UI appear at the top right corner of the screen.
Once Twitch Voting is enabled, people in your Twitch chat can type key words from the list at partybox.horse to vote for blocks that will appear in your Party Box. (This only works if you're playing in Party mode.)