To amend a PDF document, you will need a PDF editor software. There are many PDF editor software available online, both free and paid. Here are the steps you can follow to amend a PDF document using Adobe Acrobat, which is a popular PDF editor software:

  1. Open the PDF document you want to amend in Adobe Acrobat.

  2. Click on the "Edit PDF" tool in the right-hand pane.

  3. Use the tools available in the editing pane to amend the text, images, or formatting as needed.

  4. Save the changes you made by clicking on "File" and then "Save".

If you do not have Adobe Acrobat, there are other PDF editor software available online, such as Nitro Pro, PDF-XChange Editor, and Foxit PhantomPDF. You can choose the one that suits your needs and follow similar steps to amend a PDF document.