Adobe InDesign's built-in colour and prepress capabilities make it a good program for people who work with commercial printers. Among other things, it can add crop marks in the print dialogue box. Crop marks are lines that tell you where to cut to get the correct size. An InDesign script will help you get what you need with a push of a button.
Check InDesign to see if the script you need is already installed. With the program open, go to View>Automation>Scripts. This opens the Scripts palette.
Check the palette for the Crop Marks script. These are often already installed.
Install your InDesign or Creative Suite CD if it is not already installed. Drag the script into your script folder.
Select the object or objects from your file that you want to draw crop marks around. Double-click on the Crop Marks script in the palette.
Enter your requirements in the dialogue box and hit OK. Your marks will be matched to your specifications.
If your object is square, create a custom page size and let the Print box handle the crop marks. You can make crop marks around an entire group of objects with this script without joining them together. If you want a copy of your file without crop marks, save it before you run the script.