You can upgrade existing 64-bit installations of Windows 7, or 8.1 to Windows 10.
You need at least 10 GB of free space on your Windows partition.
Windows 10 is available from Microsoft as an ISO file and a USB flash drive.
You need an ISO file of the 64-bit version of the Windows 10 installer to install Windows on your Mac.
Maybe to an FTP or SFTP server, or the cloud via Amazon S3, or using Web DAV. We tuned and tweaked the new Transmit Twin-Turbo engine to get you hauling up to 25 times faster.² With the new Transmit Disk feature, you can now mount any of your favorites in the Finder itself, even if Transmit's not running.