How to automatically go to the last edited position on file open in Word?
You don't need VBA for that:
After opening the Word document, press Shift+F5.
The cursor should then be positioned at the last editing place.
For an alternative to Application.GoBack:
Word works by storing a built-in bookmark called \PrevSel1
in the document, which it can then return to.
Instead of using the Shift+F5 shortcut, you can just go to it:
Selection.GoTo What:=wdGoToBookmark, Name:="\PrevSel1"