To redact a PDF, you generally need to use software that provides a redaction tool to permanently remove or black out sensitive information. Here is a common process using Adobe Acrobat Pro, one of the most popular tools for this purpose:

• Open your PDF in Adobe Acrobat Pro.
• Go to the Tools menu and select the Redact tool.
• Select the text or images you want to redact by dragging or double-clicking.
• You can also use the "Find Text & Redact" feature to search for specific words, phrases, or patterns like phone or Social Security numbers and redact all instances automatically.
• After marking all items for redaction, apply the redactions. This will permanently remove or black out the selected areas.
• Save the redacted document, preferably with a new filename to preserve the original.
• The redacted information is then permanently removed and cannot be restored.

There are also free online tools like Xodo or Smallpdf that allow uploading your PDF, marking redactions, and downloading the redacted file without needing specialized software. However, Adobe Acrobat Pro offers more features and control for secure redaction. In summary, the core steps to redact a PDF are: open the file, use a redaction tool to select sensitive information, apply the redaction, and save the final file. This process ensures the sensitive content is permanently removed and concealed in the shared PDF.