Open the deactivation settings
Find the active survey in the Surveys section and select Go to deactivation.

Set or change the end date
If no end date has been set yet, choose Set end date and pick the date on which the survey should close.

Deactivate now closes the survey immediately. If the result notification is switched on for this survey, deactivating now does not send it — use an end date if you want employees to be notified that the results are available. See How can I inform employees that a survey has ended and its data can be viewed?