How can I upload save files into a usb?
Solution 1:
Yes, you can use a USB drive to store save games on an Xbox 360.
There is an Xbox Support article that describes how to do it. The USB drive must be at least 1GB, not bigger than 2TB, and formatted FAT32. If your drive meets those requirements, plug it in to your console and it will show up another storage device. You can move games and save files by going to Settings, then Storage (I think - it's been a while since I've done that).