Format disk

Find where your disk is located, using lsblk or mount

In linux disks are often refered to /dev/sda (computer's hard-disk), /dev/sdb, /dev/sdc , etc

In Mac /dev/disk1 is the computer's hard dis, followed by /dev/disk2 , /dev/disk3

To make a file system simply do:

sudo mkfs.msdos /dev/sdb

sudo mkfs.vfat -I /dev/sdb

-I allows making filesystem on entire device