After you have collected the necessary data, you probably want to close to survey. When the survey is closed, respondents can't see it anymore. Here's how you close a survey:
On the home page click Surveys and you will see all of your surveys. Open the survey you want to close by hovering the mouse over the top of the survey and clicking the arrow.
If the survey has been online, you will see the following view:
Click the circled tab Online and the following window will pop up.
If you are sure that you want to set your survey offline, click Set offline button. Notice that putting a survey offline, will pause all the share links.
If the survey is closed, the survey will look like this for the respondent who opens the link to the survey: