Placing a dark rectangle over a private number is not the same as removing that number from a PDF. For text redaction in Preview, use the dedicated Redaction Selection tool and verify the saved result.

Work on a clearly named copy

Keep the original in a private location and create a separate copy for sharing. Give the copy a name that makes its purpose obvious. Confirm that you have opened the copy before applying irreversible changes.

In Preview, show the Markup tools and choose Redaction Selection. Apple's macOS Tahoe 26 guide describes this as removing selected text permanently once the document is closed. Ordinary shapes and annotations have different behaviour and should not be treated as an equivalent privacy control.

Mark every occurrence of the sensitive text. Check repeated headers, summary pages and attached correspondence, not only the first visible account number. If the document is an image scan or the required content cannot be selected appropriately, stop and use a tool suited to that document rather than assuming a decorative overlay is enough.

Inspect the actual outgoing file

Save, close and reopen the redacted copy. Read every page and search for the sensitive term. Where the PDF has selectable text, try copying the affected area into a temporary plain-text document and inspect what remains.

These checks help catch common mistakes, but they are not a complete audit of every possible PDF attachment, metadata field or hidden object. For highly sensitive documents or a required formal sanitisation process, use the approved document-handling workflow.

Make sure the filename itself does not reveal the information you removed. Before attaching or uploading, preview the selected file again so you do not accidentally choose the original beside it.

Retain the private original according to your own recordkeeping needs. The shareable copy and the source record serve different purposes.

Sources: Apple's Preview annotation and redaction tools and PDF text-selection guide.

For help with your Mac, contact AEPC in East Auckland or call 027 908 8880 to discuss your requirements.