Answer: Most printers would probably prefer a Press Quality PDF (Portable Document Format) version of your design, but they might also accept files in other CMYK-compatible formats, such as high-resolution (minimum 300 dpi) JPEG or TIFF files.
To export your InDesign document, go to File > Export on the main menu and choose Adobe PDF (Print) from the Format drop-down menu in the Export window.
In the Export Adobe PDF window that opens, choose [Press Quality] from the Adobe PDF Preset menu.
You should also make sure to export your print-ready file with the Bleed included. If you’re exporting to a PDF format, you can check the option in the Export window to include a bleed.
You can also choose to include Printer’s Marks in your exported print-ready file, which includes trim and crop marks, center marks, and page information. These can be really useful to the printer when preparing your work for the press.
If your printer has requested the original InDesign, or ‘native’, files, this is because this gives the printer the freedom to re-export the file if they need to make any minor technical adjustments. You will need to Package your InDesign file before you send it.
(I know this is for PDF, but it works with JPEG too :) )
Hope this helps!
