What's the difference between third-party surveys and follow-up questionnaires?

1. What's the difference between questionnaires and surveys?
2. What is follow up survey in research?

What's the difference between questionnaires and surveys?

A questionnaire is the term used to describe the set of questions you're asking an individual. A survey is the process of collecting, analysing and interpreting data from many individuals.

What is follow up survey in research?

Survey follow-up questions are questions that the researcher asks to gather additional information from a participant when doing research.