Create fillable or editable fields in a PDF

I believe OpenOffice Writer can create fillable PDFs, though it may be lacking some features that you may be looking for such as emailing the output.

The basics are:

1. Create a new OO Writer document
2. Enable the Forms toolbar: View → Toolbars → Form Controls
3. Create your form
4. Export as a PDF

Here's a detailed tutorial:

http://openoffice.blogs.com/forms_fromscratch.pdf

In order to add form fields to an existing PDF, you can install the pdf importer extension for OO writer:

sudo apt-get install libreoffice-pdfimport

I just tested that and it works fine with LibreOffice 3.

By far the simplest way to do this is with Xournal. You type or draw in a layer above the PDF, then export the PDF + your layer as a new PDF. It looks very neat and it is easy to use. Here is a screen shot of the UI with a simple line of text added to your example PDF.

Download and install Master PDF Editor from here, e.g. the 64-bit version with QT 4.6

cd; wget http://get.code-industry.net/public/master-pdf-editor-3.5.81_amd64.deb
sudo dpkg -i master-pdf-editor-3.5.81_amd64.deb
sudo apt-get install libqt4-svg

• Create new PDF or edit existing ones.
• Add and/or edit bookmarks in PDF files.
• Fast and simple PDF forms fill out.
• Changing font attributes (size, family, color etc).
• Encrypt and/or protect PDF files using 128 bit encryption.
• Convert XPS files into PDF.
• JavaScript support.
• Dynamic XFA form support.
• Validation Forms and Calculate Values.
• Add PDF controls (like buttons, checkboxes, lists, etc.) into your PDFs.
• Import/export PDF pages into common graphical formats including BMP, JPG, PNG, and TIFF.
• Signing PDF documents with digital signature, signatures creation and validation.
• Free PDF Editor on Linux (for non-commercial use)

You can try to OCR the scanned image to convert it to editable text - but that often involves a bit of correction later to fix the mistakes, especially with forms. As discussed in comments below, use the form controls in Libreoffice to add fields to the form if you want to generate a pdf form that can be filled out.

or, what I think I would do, - you could just edit the image (cut'n'paste from the PDF) in a paint/drawing program (maybe LibreOffice Draw?) and insert text at the appropriate points. LibreOffice can convert it back to a PDF as well, as a bonus.