Adobe Acrobat's extremely popular Portable Document Format (PDF) can be used to generate or compose a digital version of just about any document type imaginable--everything from manuals to sheet music. PDF files are virtually interchangeable with their physical counterparts. And just like physical documents, sometime sensitive data may need to be blocked out of the PDF document before it's distributed. Using Adobe's Acrobat software, you can redact sensitive information from your PDF files.
Use the redaction tool in Adobe Acrobat Pro 8 or 9. By enabling the Redaction toolbar--View>Toolbars>Redaction--you can simply highlight portions of the PDF file to block out, and then apply the redaction. And the "Examine Document" feature in the Redaction toolbar can save you some time--it allows you to search for keywords in the document to redact.
Use the highlight tool to block out sections of a PDF file in older version of Adobe Acrobat Pro. Simply highlight a text selection, change the highlight color to black, save the PDF as TIFF files, and then convert them back to PDF. The TIFF conversion process combines the two layers of the PDF document--the text and highlight layers--into a single layer.
Use a third party plug-in or utility such as AutoRedact or Informatik PDF Markup to redact content in free editions of Adobe Acrobat. Third party PDF redaction applications not only fill the void in standard editions of Acrobat, they typically generate backup copies of the PDF file as well.