If you use an open question type (open question large, small or input fields question) then the field for the respondent is an empty field. You can get a standard here enter text by selecting 'Default answers' in the 'Questions' menu and fill in a text for the open questions. For example, you can think of "Type your answer here" or "Length in centimeters".
Create default answers
Go to 'Questions' and 'Standard answers' in the menu.
Select the answer in which you want to place a standard text.
Enter the desired text in the 'Default value' field.
When the respondent selects the field, the default text disappears. the own answer can be typed.