We are manipulating our Word 2007 documents from .Net using Word Interop. Mostly doing stuff with fields as in:
For Each f In d.Fields f.Select() //d
You can use the predefined bookmark:
EndOfDoc oDoc.Bookmarks.Item("\endofdoc").Range
Other predefined bookmarks:
ActiveDocument.Bookmarks("\Para").Copy "currpara"
https://msdn.microsoft.com/en-us/VBA/Word-VBA/articles/predefined-bookmarks