how to send two forms with one click (script ninjaforms id)

I partially stole this answer from SO

$("#idForm").submit(function(e) {

var url = "path/to/your/script.php"; // the script where you handle the form input.

$.ajax({
       type: "POST",
       url: url,
       data: {
                 form1: $("#idForm").serialize(),
                 form2: $("#idForm2").serialize()
       },  
                 // serializes the form's elements.
       success: function(data)
       {
           alert(data); // show response from the php script.
       }
     });

e.preventDefault(); // avoid to execute the actual submit of the form.
});

So basically you prevent the normal submit of your forms, serialize it’s content to json and send that in an ajax call to the server.