Engraving is done in double line Century block.  You can have one, two or three initials engraved in a straight line.  For example, John W. Smith would be engraved  JWS.   Amonogram must have three initials and would have the last name initial in the center and slightly larger than the other initials so that John W. Smith would be engraved JSW.  This style tends to look better on an oval.