On the PC
You will have to progress up the Citizen Talent Track in order to fully enable trading.You can check your progress on the Talent track by clicking on the image of your avatar on the bottome task bar and then clicking the Talents icon.
Habbo staff cannot "make" a trading pass for you. You must follow the information given here.
On Android and iPhone/iPad
In order to gain access to the talent track, you need to click on someone and select trade. If you do not have your trading pass, the Citizen Talent Track will open. Follow the steps and you will get your trading pass in no time!