Hi Sharon,
What format is the letterhead now?
You should be able to capture it as a png file by taking a screen shot of the part to want to capture.
To take the screen shot:
Open the file in MS Word, and show the page containing the letterhead.
Place the pointer at the top left corner of the part of the page you wish to capture.
Press shift-command-4.
The pointer will change from an arrow to a crosshairs.
Press and hold the mouse button and drag the crosshairs to the bottom right corner of the area you want to capture.
When the selection rectangle frames the image you want, release the mouse button to capture that image.
The image file will be saved to your Desktop as a .png file with the name Screenshot, followed by the time and date on which it was taken.
You'll be able to import it to your MS Word document as you would any other image file, then resize it if necessary and position it where you want it.
Regards,
Barry