Hi Zahra,
While sharing with everyone does allow anyone to submit to the survey, a person would need to search ArcGIS Online in order to find it.
It is possible to include a hidden question to store a validation value in a survey, and then include the value as part of the link sent to people (see Understanding Survey123's custom URL Scheme for providing values as part of a link); if you set the other questions in the survey to not relevant unless the code was present, that would hide the form otherwise.