From your dashboard, click on Ticketed Events, then click "Manage" on the event you wish to manage.
Click on "Tickets"
Select the ticket you wish to have the custom questions by clicking on the pencil icon.
Then, select "Custom Questions."
Select the type of element you'd like to add and fill in the fields.
Make sure to check that everything is correct, then press "Save."
That's it! Now, the ticket purchaser and their guest will be able to answer the additional question because it will appear per ticket purchased as shown below.
Click here for a step-by-step guide on how to view the answers to these questions!