From stream view, click Q&A from the right sidebar and then click start a Q&A
Q&A topic: The question you’d like to ask you viewers
Duration: This is the amount of time that users will be able to respond to your question
Custom duration: If you’d like to set a specific day and time for the Q&A to end, you can set a custom duration
Require credits to respond: If you’d like to charge users credits in order to respond to the Q&A you can specify the amount of users you’d like users to pay