Thank you for your question. While I did not see a built-in way to accomplish this in Prestashop, there are Modules available for purchase in the official Prestashop Addons page.
There was one called Module Checkout Fields.
If you have any further questions, feel free to post them below.
You can check this custom checkout fields module by FME here: http://www.fmemodules.com/en/51-custom-fields.html it is also available at official PrestaShop market place: http://addons.prestashop.com/en/front-office-features-prestashop-modules/19008-custom-fields.html