To correctly generate reports, the recommended version of the wkhtmltopdf utility needs to be installed. Its name stands for Webkit HTML to PDF. Odoo uses it to convert a rendered HTML page into a PDF document.
Some versions of the wkhtmltopdf library are known to have issues, such as not printing page headers and footers, so we need to be picky about the version to use. Since Odoo 10, version 0.12.5 is officially supported and is the officially recommended one.
The official Odoo project keeps a wiki page with information and recommendations about wkthtmltopdf usage. It can be found at https://github.com/odoo/odoo/wiki/Wkhtmltopdf.
Unfortunately, the odds are that the packaged version provided for your host system, Debian/Ubuntu or any other, is not adequate. So, we should download and install the package recommended for our OS and CPU architecture...
