Well, you need to go through a modeling agency which has Hugo Boss as their client.
How Do I Apply To Be A Hugo Boss Model?
You should start by learning as much as you can about the modelling industry in general - learndirect has some straightforward information, but there is plenty of advice available. There are also some dodgy agencies about, so do be careful about parting with money!
If you have a special interest in Hugo Boss you could contact them through their talent pool, though this isn't specifically for modes.
If you have a special interest in Hugo Boss you could contact them through their talent pool, though this isn't specifically for modes.