Modal Dialog Box for SharePoint List — New Item

How to add a button to a SharePoint Application Page that opens a Modal Dialog Box for creating a new List Item.

1. Add the following JavaScript code to your Application Page (either by using a CEWP or a Script Editor Web Part — your choice)

1. Add the following HTML code to your Application Page (using a CEWP)

Thanks to the SharePoint Developer Team via SharePoint dev blog — How to Open a List Form in a Modal Dialog Box.