View.ShowCropMarks Property (Word)
Returns or sets a Boolean that represents whether to show crop marks in the corners of pages to indicate where margins are located. Read/write.
Displaying crop marks does not allow a user to change the margins by dragging the crop marks. Crop marks are only displayed to indicate where margins are located in the page. This property corresponds to the Crop marks check box in the Advanced tab of the Word Options dialog box.
Crop marks are shown by default in East Asian languages and are off by default in all other langauges.