Web form that could be filled without authentication

I created a simple survey on KoBo. Now I would like to send it to a couple of people using a link in an email. And I would like these people to be able to fill the WebForm (Enketo I guess) without being asked to login to Kobo. Is it possible ?
The survey is anonymous. Is there a smart way to ensure that people don’t fill the form twice ? But this is a secondary issue that is not very critical in my context.
Thanks in advance for your help.