Ubuntu has already an application called Startup Disk Creator, but this can only be used to make Linux bootable USB drives. To make a Windows bootable USB there is an application called WinUSB but it hasn't been updated for a while.
The following guide has been updated and works on any Linux distribution as long as it has GRUB and GParted installed and can make bootable USB for any Windows version newer than Vista: Windows Vista, Windows 7, Windows 8, Windows 8.1 and Windows 10. UEFI boot is only supported for Windows 7 x64 and newer.
Before starting, let's mention that there are two types of boot methods. There is the MBR code type where the bootable executable is stored in a reserved section at the beginning of the storage device. And there is the EFI type, where the boot loader executable file is stored at a standard path in an FAT32 filesystem.
You must decide in advance what you will use. There are some variables for each boot type. If you have no idea what to use, the most common setup that works with unmodified Windows sources, is
msdos partition table with
fat32 filesystem and flag the partition with
boot. In this way you will get both an MBR and UEFI bootable drive.