A simple Stop Watch question will give you the option to start and stop the timer.
Go to: Login >> Select Survey >> Edit Tab >> Workspace >> Add Question >> Advanced >> Mobile >> Stop Watch
This is how it will look on the QuestionPro Offline App:
When you add questions to a survey, by default, Force Validation option is turned off. When this option is not enabled, respondents can continue with the survey without selecting answers. If respondents go through all the pages in the survey without selecting answers, the response is still considered complete. You can enable Force Validation option to make a question required so that respondents can continue with the survey only after responding to the questions. Click on the Validation option and then select Force Validation option to enable it.
This feature is available with the following licenses :