For dynamic content check out this article instead.
You can add links in email messages that are unique for each contact. For example:
https://www.mysurvey.com/UNIQUEID
You need to set up the unique text as a custom field and import data into this field, then you can and add it as a merge field for your link using this format: {@my-FIELDNAME}
For example if your field is called: surveyid then the link becomes:
https://www.mysurvey.com/{@my-surveyid}