Open end questions are used to collect respondents' opinions, thoughts or messages. You can set maximum or minimum characters or resize the text box.
There is no top limit on characters numbers. If you think respondents may give long messages, please change question type to Essay box.
To avoid invalid answers, you can set text validation on open end questions. Answers must fit the format you set or respondent can't submit or proceed.
Question type depends on your questions. Comparing to multiple choice questions, you can get detailed and various answers from open end questions. But on the other hand, you need to put in more engergy and time to analyze open end questions. So if unneccessary, we recommend you to use multiple choice questions instead of open end questions.