What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
If I understood you correctly, you are looking to add several other options to your already existing checkbox.
If that is true, then yes (ja) that would be possible.
All that you should do is to click on the field and then click on the Options (Optionen) button in the toolbar.
Once you add all of the fields that you need / or remove the ones that you do not, all you need is to click on OK to confirm the change and as you do, you will see the change applied to your form field and after Saving (Spaichem) the form, you will see the change applied to your form as well.
Do let us know how it goes and if you happen to have any further questions :)