This is the module you should fill out in the case you have something to declare at the Ukrainian customs. (red corridor)
Usually you have to fill out this module when you travel with a big sum of money or very precious items.
If you travel just with your personal things… mobile phone, notebook… than you don’t need this declaration.
In this case pass through the green corridor.
You have also to fill out this declaration if your luggage is lost.
This customs declaration is in Ukrainian but at the airport you will be able to find also the English version.
Official web site of Ukrainian Customs:
Ukrainian Customs Declaration in English: