Array - Array is a structure in which it stores multiple values in a single variable. It can be classified into three types say numeric ,associative and multidimensional array.
Ctools Automodal will help you to create popup in your site. It is an easiest way to create a popup without any burden. To Create a popup form please follow the below instruction:-
Download and install the ctools Automodal(module) in your drupal instance.
Description : By using this module You can create your own custom form in popup.