Crop marks, also known as trim marks or cut marks, are small lines or marks added to the edges of a digital document to indicate where it should be trimmed or cut after printing. Crop marks are typically used in commercial printing, where multiple copies of a document are printed on a larger sheet of paper or other substrate, and then cut down to size. Crop marks are usually placed just outside the actual dimensions of the document, to ensure that no part of the design is accidentally cut off during the trimming process. Crop marks can be added manually using design software such as Adobe InDesign or Illustrator, or they may be automatically generated by certain printing software or services.