Two ways to go about it:-
Have macro in the UserForm that after populating the 12 pages with the required information, split the document into the four parts, which would probably be best done by having a section break between each of the parts and then using code such as that in
the following macro
Sub splitter()
' splitter Macro
' Macro created by Doug Robbins to save each letter created by a mailmerge
' as a separate file, retaining the header and footer information.
Dim i As Long, Source As Document, Target As Document, Letter As Range
Set Source = ActiveDocument
For i = 1 To Source.Sections.Count
Set Letter = Source.Sections(i).Range
Set Target = Documents.Add
Target.Range = Letter
Target.Sections(2).PageSetup.SectionStart = wdSectionContinuous
Target.SaveAs FileName:="Letter" & i
Target.Close
Next i
End Sub
The second way would be to save a template containing the user form in the Word Startup Folder so that it was treated
as an add-in and create a separate template for each of the four documents and have code in the user form create new documents from each of the templates, populating each with the data that was inserted into the form and then saving each one in turn.