Page Numbers

The PageNumbers property of the HeaderFooter object returns a PageNumbers collection, which holds all of the PageNumber objects for that particular header or footer.
In most cases a header (or footer) will contain a single pagenumber object (if any) denoted by PageNumbers(1).
To add a page number to a header or footer
The Add method inserts a text frame containing the page number field into the specified header or footer
The text frame is positioned according to the PageNumberAlignment parameter.
If FirstPage is set to False a page number is not added to the first page

objPageNumbers.Add PageNumberAlignment:=wdPageNumberAlignment.wdAlignPageNumberLeft, 
                   FirstPage:= True | False 

If you want to insert a page number within some other text then you can use the Fields.Add method using the type wdFieldPage

Dim objRange As Range 
   Set objRange = ActiveDocument.Sections(1).Headers(wdHeaderFooterIndex.wdHeaderFooterPrimary).Range 
   objRange.ParagraphFormat.Alignment = wdParagraphAlignment.wdAlignParagraphCenter 
   objRange.Text = "some text" 
   objRange.Collapse wdCollapseDirection.wdCollapseEnd 
   objRange.Fields.Add objRange, wdFieldPage 
   objRange.Move wdStory 
   objRange.InsertAfter "some more text" 

Inserting Page Numbers

activedocument.footnotes.add range:=myrange, text:="my text" 
With Selection.Sections(1).Headers(wdHeaderFooterPrimary).Pagenumbers 
   .NumberStyle = wdPageNumberStyle.wdPageNumberStyleArabic 
   .HeadingLevelForChapter = 0 
   .IncludeChapterNumber = False 
   .ChapterPageSeperator = wdSeparatorType.wdSeperatorHyphen 
   .RestartNumberingAtSection = True 
   .StartNumbering = 5 
End With 

ipageno = Application.Selection.Information(WdInformation.wdActiveEndPageNumber) 

   oFooter.PageNumbers.Add PageNumberAlignment:=wdAlignPageNumberCenter, _ 
                           FirstPage:=True 

Return the Page Number at the current cursor position

Selection.Information(wdActiveEndPageNumber) 
ActiveDocument.Content.Information(wdInformation.wdActiveEndPageNumber) 

Return the number of pages in the active document

Selection.Information(wdInformation.wdNumberOfPagesInDocument) 

ActiveDocument.BuiltInDocumentProperties("Number of Pages") 

The last method is the most reliable, but also the slowest

ActiveDocument.Content.ComputeStatistics(wdStatistic.wdStatisticsPages)