How can I create auto calculate for the marks?

If you're planning to create a test form, you can use the Quiz App. Here's the link: https://apps.jotform.com/app/quiz_form. This app will help you convert an existing form into a Quiz form. Please check this guide: Turn-Your-Form-into-a-Quiz-or-Exam.

We do have a widget called Form Calculation. Here's a related guide: How-to-Perform-Form-Calculation-Using-a-Widget.

Hope that helps. Thank you.