How to: Add Windows Forms to a Project(Inserting a Form into a Project)

Inserting a Form into a Project

To insert a form into your project

1. From Class View, select the project to which you want to add the form, and click the right mouse button.
2. From the shortcut menu, click Add and then click Add Class.

   If the New Form command is not available, your project may be based on the Active Template Library (ATL). To add a form to an ATL project, you must specify certain settings when first creating the project.
3. From the MFC folder, click MFC Class.
4. Using the MFC Class Wizard, make the new class derive from CFormView.

Visual C++ adds the form to your application, opening it inside the Dialog editor so that you can begin adding controls and working on its overall design.

Sources: https://msdn.microsoft.com/en-us/library/fhxbke21.aspx