How to edit a signature file into a PDF document

A paper form has been sent to me to be filled out.

I scanned it as a PDF file into my Mint Maté 17 box, opened it in LO Draw (v. 4.2.7.2), typed the necessary data into the relevant locations, then re-exported the edited file as PDF.
The edited file, containing the added text, opens properly in other applications such as Adobe Reader or Document Viewer.
In Draw I then tried to add a PNG signature file to the PDF, but the "File" option of the "Insert" menu is greyed out, so that I don't know how to add the signature file to the PDF. I cannot do it manually because my handwriting is impaired.

What should I do?

Thanks for helping.

jdh

How about Insert- Image- From File ?

Or click on the icon at the bottom of the page, near the right end, says "From File" when you hover over it,

Keith

Hi John,

Master PDF Editor for Linux will let you do all this and more.

Alex

And for those on Mac, just use the PDF Viewer (Preview) that Apple
supplies, as you can now add signatures directly from a scanned source
in OSX 10.10.

Previous to OSX 10.10, I used FormulatePro to insert a handwritten
signature I'd created in Draw and saved as a PNG.

Alex