try to grab a screenshot or render your model from the side view or where you want the engravement to be.

bring that image into photoshop

make a layer in photoshop and draw the engravement in some fairly high resolution. Use a black clor to define the places the engravement should go down to the sword, white where it should go out of the sword.

make the background of the image grey RGB: 127, 127, 127

since the grey is rgb 255/2 = 127.5 ~ 127 it will be neither up (white = 255, 255, 255) or down (black = 0, 0, 0) so the grey will be neutral bump/displacement.

crop the image to fit the geometry

save as TIF (dont save the tiff with layers, since Maya does not understand TIFF files with layers)

in Maya create a shader with a bump or displacement map using the newly created TIFF image

Topics you could look into using the HELP files is :

Bump mapping
Displacement mapping
Creating projection
UV's

This should get you started.. and .. Good luck