Preflight and Package your InDesign Documents

Before printing, exporting a PDF or handing off a document to another individual or service provider, you can perform a quality check on the document. "Preflight" is the industry-standard term for this process. While you edit your document, the Preflight panel warns of problems that can prevent a document or book from printing or outputting as desired. These problems include missing files or fonts, low-resolution images, overset text, and a number of other conditions. 

Preflight warnings are displayed at the bottom left of the document window, next to document navigation. The Preflight panel is under the Window menu > Output:

InDesign's Preflight Panel showing a modified link error.

View and resolve preflight errors in the error list. Only the categories with errors are listed. You can click the arrow next to each item to expand or collapse it.

Note that Preflighting does not necessarily detect colorspace or resolution problems. View image details in the Links panel to detect those errors.

Package files

You can gather the files you’ve used, including fonts and linked graphics, for easy handoff to your instructor, another individual or a service provider. When you package a file, you create a folder that contains the InDesign document (or documents in a book file), any necessary fonts, linked graphics, text files, and a customized report. This report, which is saved as a text file, includes the information in the Printing Instructions dialog box; a list of all used fonts, links, and inks required to print the document; and print settings.

Go to the File menu > Package:

InDesign performs an up-to-date preflight check. The Package Inventory dialog box indicates any detected problem areas. You can also give your service provider a composite PDF file made from your document or a PostScript file.

InDesign's preflight prior to creating the file package
detects two files that uses RGB color space

Click on the menu in the left column to investigate
and resolve any problems.

You can also configure preflight settings to define which conditions are detected. These preflight settings are stored in preflight profiles for easy reuse. You can create your own preflight profiles or import them from your printer or another source. 

See the Adobe.com website below for all about preflighting and packaging files.

Adapted from http://helpx.adobe.com/indesign/using/preflighting-files-handoff.html