Q:

Word Macro to add predefined content at the end of document on click of button

I have an document in word, which has some fields to be filled, and an button to which I want to assign a macro. When that button is clicked, that same form with empty fields needs to be appended to the end of document, including the button (which can be clicked again and do the same thing).
Here is the document I have:
https://drive.google.com/file/d/0B_2kyqxMx5x4UkxfOHJhOGVPdnc/view?usp=sharing

A:

The main problem with what you want to do is dynamically linking the button to the macro code to be executed. The most obvious type of button to use is the legacy ActiveX control in the Ribbon's Developer tab. But that requires its own procedure entry in the document's ThisDocument class module. While it's possible to add code to modules "on the fly" this involves disabling a security option.
A more straignt forward approach is to use the MacroButton field. This creates a clickable text within the document. It can display text or a graphic (so that it looks like a button) and is assigned the name of any public Sub that takes no parameters:
 { MACROBUTTON NameOfMacro Click here }

Ctrl+F9 to insert the field code brackets; Alt+F9 to toggle between field code and field result.
Graphics in Word 2010 and later:* The was a change to the graphics engine in Word 2010 which affects the behavior of graphics objects in the MacroButton field. Clicking the object triggers the Ribbon utility for working with graphics - the field code no longer "hides" the graphic. There are a number of ways you can work around this:

Use an IncludePicture field (which works with the old graphics format) to bring in an outside picture file. Once the linked picture is in the field it can be converted to a static picture by selecting the IncludePicture field and pressing Ctrl+Shift+F9. Word respects the old graphic format and the picture is click-able.
{ MacroButton NameOfMacro {IncludePicture "C:\\Path\\picture.jpg" } }
Use the old *.doc file format. Note that this will restrict some of the things that can be done with the document, but it will force use of the old graphics engine.
Instead of a MacroButton field, use the WindowBeforeDoubleClick event or WindowSelectionChange event to run the code.

*With the exception of unlinking the IncludePicture field (which I discovered myself), this information came from this discussion on the Microsoft Answers site
If you want to run the macro with a single rather than a double-click (the default) you need to run the following line of code. This applies to the entire Word application and needs to be run everytime Word restarts. You could put it in an AutoNew macro in the template / AutoOpen macro in the document:
Application.Options.ButtonFieldClicks = 1

The simplest way to store the entire content you want to insert repeatedly is as a Building Block (formerly known as AutoText). 
BuildingBlocks are stored in templates. If your document is being created from a template, that would be the logical place. Another possibility would be a special template you use for this purpose. Normal.dotm can also be used but keep in mind this does sometimes get removed.
(Note: if you're using a template for the document that would also be the best place to store the macro attached to the macro button.)
Once this is set up, all your code needs to do is insert the BuidlingBlock at the end of the document.

