I want to try a thing with 2 arduino uno but I cant buy stuff without any knowledge about it.
I need to create 2 boxes :
1 with a usb in and usb out (female)
and 1 with only a usb out (male)
The 2nd one must be linked by usb to the 1st one and the 1st one must be linked to a device like a battery (external type, for phone or something like this (5V out))
The Arduino DUE and the Zero have native USB ports as well as USB ports for programming. Otherwise you will need something like a USB host shield for other Arduinos.
PaulS:
What is device 2 supposed to do? What is device 1 supposed to do? Why is USB between 2 and 1 the proper answer? I'm going to guess that it is NOT.
The both devices must formed a whole device (like a battery) to power an already done device via USB.
It's for a little escape game.
If it's only POWERED over USB, no actual data exchange, indeed you don't need a USB out on the Arduino side. Just connect the 5V and GND wires of the cable that goes to the USB device.