You need to sign up for an account if you want to use Prezi. Most people sign up for the free account, called Basic until they get a handle on it and decide which Prezi subscription level is best for them. Speakers and Sales professionals often use Prezi on the road. They never know for sure if they’ll have an Internet connection. They might need to present their prezi offline. For these users, I recommend either the Prezi Plus or Prezi Premium account. These subscription levels will allow you to download a desktop version of Prezi that you can edit your Prezi offline. Anyway, if you want to make a smart decision, you can always have a look at the Prezi Licenses article, to decide which account will fit you best.
Prezi for Windows and Prezi for Mac gives you local access to your Prezi account. Instead of opening your browser and going to Prezi.com, you run Prezi offline on your desktop or laptop. This lets you download Prezi to present and edit your prezis offline anytime, anywhere. If you need to make a quick change to your presentation, you can fire up your laptop and edit it even if you’re not online. The next time you connect to the Internet, your offline prezis will sync with your online account.