Polls in Zoom can be created before and after the meeting is started. The only thing that you need to understand is that you will be making the polls on a desktop browser. So, even if you are using a desktop client, once you select the option to create a poll, you will be redirected to your default browser. Creating a poll, however, does not automatically run it. To run a poll, you have to have an active meeting. Again, you won’t be able to launch a poll before the session has started.