How do I add a signature section so customers can sign a numbers document ?

Ok, I kept digging until I figured it out.

1. Fill in your fields in numbers and press the tools / email spreadsheet.
2. choose PDF.
3. Email it to your self.
4. Download a application like "Easy Sign" (I tried this one and a few others and this was the easiest to use).
5. Open up the email and hold your finger on the document you emailed earlier until the "Open in "Easy Sign"" opens up.
6. Follow the directions in "Easy Sign" after that (very easy).