I need to take membership

Are you planning to upgrade your account? If yes, then please refer to this guide: How-to-Upgrade-My-Account.

Or are you referring to a membership function where your user can login to the form using the registered username and password?

If yes, then I'm sorry to inform you that this functionality is not available in JotForm. We don't have a membership feature. You can use JotForm though to have a registration or sign up form. You can check MemberKit and verify if that is what you need.

Hope that helps. Thank you.