This document defines a questionnaire as a set of questions used to gather responses, attitudes, or preferences from a particular group regarding a specific subject. Questionnaires are used for business surveys, assessing social, economic, or psychological conditions, and determining levels of satisfaction. There are different types of questionnaires including social, educational, and business surveys. The document provides guidelines for effective questionnaire design, such as using clear, concise, and logically ordered questions that are relevant to the topic of interest. Common question types and digital questionnaire tools are also outlined.