After you download Taskheat from the App Store, you can start the two-week trial. It allows you to use the app without any limitations in functionality during all trial periods.
When the trial period ends, you will still be able to access your data in a read-only mode. It means that even if, for some reason, you decide not to purchase the Full Version, you can safely access, retrieve and export your data you've entered in Taskheat.
You don't have to do any additional actions to stop the free trial period if you do not want to continue using the app.