All Joomla sites have ready-to-use polls. To create a new poll, simply go to Components>Polls and click 'New' at the top right.

After you've filled in the fields as above, click on 'Save' at the top right to save the new polls.

How do you put the polls on your site? Go to Extensions>Module Manager and click 'New' at the top right. Select 'Poll' as the type of item you want to create, and click 'Next'. At the top right, under Module Parameters, select the name of the poll you just created. Where would you like the poll to appear? Choose the position in the Details section of that new module form. You will probably want it to appear on the left. Click Save at the top right and your poll will now be visible.