Hi Rudolf,
Entirely possible in Word.
When you Insert | Picture | From File, it comes in with the Layout set to
"in line with text", which means you cannot write on top of it. Double-click
the image to bring up the Format | Picture dialog and change the Layout to
"behind text". Then you should be fine, it should act pretty much like the
Word Art image.
Make sure you insert the image with the cursor in the header/footer, so that
it will repeat on every page, then drag it wherever you want.
Any image Layout setting other than inline with text is a floating image,
which means it is out of the text stream and can be dragged to anywhere on
the page, and is denoted by empty outlined boxes around it on selection,
instead of the solid black boxes and line that come up when you select an
inline image.
Side note:
A) most printers will not print all the way to edge, so if you want this
look to print, you'll probably have to accept a small blank margin.
Side notes on templates
1) I hope you are not making these changes to the Normal template, as that
will mess up your envelopes and labels. Also, don't try to save this as the
default template, please.
2) once you get the template set up as you like, save it in the My Templates
folder. Use File | Project Gallery to open a clean new doc based on this
template. Once this works smoothly, record a macro of the Project Gallery
process, and assign that macro a keyboard shortcut, for easy access (even
cmd-N if you want), or put it on a toolbar. Post back if you need more
guidance with that, although Help will walk you through it also.
PS. If one question is a waste of time, they all are. It's far more fun
sorting out how to use Word than troubleshooting.