Hi Zayidu,
There are standard functionalities in EWM system which you can configure to get it, printing on HU label is controlled by Post Processing Framework (PPF) in EWM where in you can link it with smart form and at what point of time it should print.
Read about PPF in EWM to get basic idea on how does PPF work. You need to have some basic understanding of such things only then the solution provided by experts will be much helpful to you.
BR
Anoop