No! You cannot create a normal.dotm file in this manner. Only Word can create a normal template.
You can either add the code and userform to the existing normal template or you can create a global template (saved in the Word startup folder) with the code and form and that will load with Word
If you have not changed the preferred startup folder it can be located (in English language versions of Windows) by typing
%appdata%\Microsoft\Word\Startup
in the Windows File Explorer Address bar and pressing Enter.
The reason for the error is that you have created the macro in the 'userform' module of the normal template project when the userform you are attempting to call is in the Document project. You should add an ordinary module to the DOCUMENT project and put the code to show the form in that module and remove it from the normal template. Conversely you could move the userform from the document project to the NORMAL project.
form1.jpg
I would also suggest calling the macro something other than Show, which is a vba command name and which may cause some confusion e.g.
Option Explicit
Sub Show_Form()
UserForm1.Show
End Sub