The default setting for this is ‘Not Active’. This means your survey can not be viewed/opened from a shared link.
Clicking on ‘Active’ makes your survey active, meaning it can be seen/opened and completed by your users from a shared link.
You will need to click ‘Active’ when you want to actually see how your survey will look published. Preview gives you a good look at your survey but may not always show how it will look exactly when published. Open up a new tab using a shared link to your survey and you can now click through your survey to see how it looks and check added options such as ‘Logic Jumps’ performs.