Acrobat uses overlay text to overprint areas selected for redaction. One example of overlay text is a redaction code, which consists of one or more code entries from a code set. Acrobat includes the U.S. FOIA and U.S. Privacy Act code sets that you can use. You can use either codes or custom text to create overlay text. The difference is that redaction codes are text entries that you can save, export, and import. One code set can contain multiple codes.