Open the PDF in Adobe Acrobat Pro, Foxit PDF Editor, or another PDF editor
Use the Edit PDF tool
Select the text or image you want to change
Make the required edits
Save the file as an editable PDF
If the PDF is scanned, run OCR first
Convert the PDF to Word, edit it, then save it back as a PDF
Use online PDF editors if you need browser-based editing
Add form fields if you want users to fill in the PDF
Check the file permissions if editing is restricted
Save a copy to preserve the original file