Hi Zoso
By itself, Word can't do what you want. *If* your printer has a
"mirror image" or "T shirt" mode, you'll find a check box for it
somewhere in the dialog you get by clicking the Properties button next
to the printer's name in the Print dialog.
For a few labels for a circuit board, it's easier to use the Paint
program that comes with Windows. Select the text tool (the A button on
the palette) and drag a rectangle in the drawing area. Click View >
Text Toolbar, and select the font/size/bold etc. Then type your label
into the rectangle. While the rectangle is still selected, click Image
Flip/Rotate; select Flip Horizontal and click OK. You can copy/paste
the reversed type into any other application, including Word.