"FORMAT" is used to format
"FORMAT A:" will format the A: drive, or floppy drive when a floppy disk is present.
"FORMAT A: /Q" will quickly format the drive
"FORMAT C:" will format the C: drive or hard drive, you can change this letter as need be.
"FORMAT C: /Q" will format the drive quickly.
"FORMAT /?" will give you further help when using the command.