Mac - Disk Utility - macOS

You can erase and reformat an entire volume. If the volume contains data, it is deleted when you erase and reformat the volume, so make sure you create a backup of it if you want to keep the data. Mac OS Extended (Journaled): Uses the Mac format. MS-DOS (FAT): Use for Windows volumes that are 32 GB or less. ExFAT: Use for Windows volumes that are over 32 GB.