To save a file for print, follow these steps:

1. Flatten your file.
2. Convert the color mode to CMYK by going to Image>Mode>CMYK Color.
3. The publication using the image file probably will list the file types they will accept. It could be an .eps, .tif, .jpg, etc. To save the image as a particular file type, choose File>Save As, title your file in the File Name box, and choose a file type from the Format drop-down menu.