Global password protection adds a level of security and access restriction to your survey. If you are posting a link for the survey online and wish to restrict access, you can use global password protect option adding a simple layer of security.
Go to: My Surveys (Select Survey) » Edit
Select the Global Password Protect option and save.
A common password will be set for the survey. For higher security, you can use Email/Password or any other password security option.This feature is available with the following licenses :