FAT32 is a system used by Microsoft Windows for organizing files on disks and drives. You can have a drive format to FAT32 on an Apple Mac computer using Apple's Disk Utility, which comes with macOS. You can also format the drive in a variety of other formats depending on your needs.
FAT32 Vs NTFS
When you access a drive in an operating system like Apple macOS or Microsoft Windows, you'll generally see a familiar pattern of files and folders and won't have to worry about how the data is actually organized on the drive. But your operating system organizes disks according to what are called file systems, and each has different properties as far as how data is laid out on disk.
Most Windows systems format disks by default using a file system called NTFS, named for Microsoft's onetime operating system Windows NT. Macs, on the other hand, use systems called HFS+, for Hierarchical File System, and APFS, for Apple File System. Macs generally can't fully work with NTFS disks, nor can Windows computers work with the Apple file systems.
This generally doesn't matter for hard drives and other drives that sit within one computer, but it does when it comes to USB drives that will be used across multiple devices. One solution to this problem is to make sure that drives are formatted using a file system that both Windows and macOS understand. These systems include FAT32, an older file system from Microsoft, and a newer version called exFAT. The acronym FAT stands for file allocation table, which is a system that specifies where the files are on the drive.
FAT32 Formatter for Mac
If you're using a Mac, you don't need special software to format a USB drive in the FAT32 format. You can use Apple's built-in Disk Utility.
Before you format the drive, make sure there's nothing valuable on it that's not also backed up elsewhere, since all data will be lost. If you can't read the drive on your computer because of its format, you may want to find a computer than can read it to verify it doesn't have anything irreplaceable. Use caution with USB drives if you don't know or trust where they came from, because they could contain malware that could steal data from you or damage other files on your computer.
Load Disk Utility with the USB drive inserted into one of your Mac's USB ports. You may need to use an adapter if your Mac doesn't have USB ports. Select the drive from the list of drives, making sure to choose the right one, and click Erase. Specify a name for the drive if you wish, or leave it as "Untitled," and select "MS-DOS (FAT)" from the Format dropdown menu to format it in FAT-32.
Click Erase and wait until the drive is formatted. It should then be blank and ready to use.
Fat32 or exFAT
There is a newer file system in Microsoft's FAT line called exFAT. It has some advantages over FAT32. Specifically, it can store files larger than four gigabytes, which FAT32 cannot. It can also be read and written by Macs and Windows computers, so you may want to use exFAT rather than FAT32 when you're formatting a drive. It's another option in the Format dropdown in Disk Utility.
The drawback to exFAT is that some older devices and operating systems don't support it. If you are going to be using a USB drive with an older computer that won't be able to read or write to it if it uses exFAT and you don't need to store files bigger than the FAT32 file size limit, you may want to use FAT32 instead.