I noticed it's easy to make a poll for a new topic but what about one that is already going? possible?

Thank you

Yes,  just as easy. Then feature it on the sidebar.   

There's an admin setting to allow it.

8 hours ago, superj707 said:

I noticed it's easy to make a poll for a new topic but what about one that is already going? possible?

Thank you

Yes - as long as it is within the time frame (defaults to 24 hours) specified in the poll settings in the ACP.

Search for 'poll' in the ACP and click on 'Polls' to get to the settings.

How to add the poll? Edit the topic's opening post and then go to the Poll tab.