Polls are not recommended since the aim of Wikianswers is to have questions that can be asked collaboratively. If you do add a poll to a question that could not otherwise be answered, you should be aware that editing of the poll will reset the responses so that people need to vote again. See What happens if you edit a poll with responses?
To add a poll, type this where you'd usually type an answer:
<poll> Do you like polls Answer 1 Answer 2 Answer 3 </poll> Category:Polls
It will be displayed as:
You can find all polls in :Category:Polls.
See Help:Polls for more detail.