There are multiple methods of distributing Qualtrics surveys. One of the most popular methods is using an anonymized link which allows you to send a single link for all potential respondents. The downside of this type of link is that it will allow anyone with the link to access and submit a response to your survey - this means that the survey link could be forwarded to others outside of your intended respondent group, potentially skewing your data.
However, there are a couple options for restricting survey access to potential respondents.
1) You can email customized links to respondents from within the Qualtrics Mailer. Each survey invitation link is sent only to a single respondent per individualized link.