The zoom shouldn't change when typing, unless you are somehow brushing the touchpad (you could reduce its sensitivity or turn it off completely), or inadverently typing some keyboard combination.

To force a centered page at 100% zoom, place the following macros in Normal.dotm:

Sub AutoOpen()
With ActiveWindow.View
.Type = wdPrintView
.Zoom.PageColumns = 1
.Zoom.Percentage = 100
End With
End Sub

Sub AutoNew()
With ActiveWindow.View
.Type = wdPrintView
.Zoom.PageColumns = 1
.Zoom.Percentage = 100
End With
End Sub

For assistance, see http://www.gmayor.com/installing_macro.htm.

__________________
Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional