How to allow users to see data populated on a form, but do not allow them to edit it?

another question: Is it possible that FORM 2 is shown in a preview mode? so that the one that see form 2 with prepopulated fields can't edit anything on it? or how to achieve this

I can see two possible ways to achieve it, the first one is by using conditions, for example, you may choose a field and make the condition based on that field, your condition basically will disable all other fields if this main field is filled, sample condition:

The second way is disabling each field on the settings, to do this you only need to click on the field and, click on the properties icon and then click on Edit Properties. 

Now you only need to set the "Read Only" property to Yes.

Hope this helps. 

Thanks for this, another question...

You're welcome. 

Your second question has been moved to this thread: https://www.jotform.com/answers/813347. 

We will assist you as soon as possible.