Format USB for Samsung TV

Simply use Disk Utility to format it as FAT, as Macs can indeed read and write to FAT drives–they just have problems with NTFS drives.

Insert your flash drive. Open Disk Utility (/Applications/Utilities/Disk Utility), select your flash drive in the sidebar, then click "Erase" in the top bar. Select "MS-DOS (FAT)" for your format, and Master Boot Record for your scheme.

Note that the FAT file system has a limitation of 4GB file size. If you want to circumvent this whilst still being able to use OS X, format the drive as exFAT (which has a file size limitation of 128 PiB). This option has been recently hidden with 10.11, so it takes a bit more work.

Open Terminal (/Applications/Utilities/Terminal). Run the command defaults write com.apple.DiskUtility advanced-image-options 1. This gives you access to hidden features within Disk Utility. Open Disk Utility (/Applications/Utilities/Disk Utility), select your flash drive in the sidebar, then click "Erase" in the top bar. Select "ExFAT" for your format, and Master Boot Record for your scheme.