Format disk with mkpart

run for desired disk
parted /dev/sdx

creation of label depends wheter disk is bigger than 2TB choose between msdos or gpt
mklabel gpt

than format the partition, you can manually select size or use %
mkpart primary ext4 0% 100%

last step is format partition table with mkfs
mkfs.ext4 /dev/sdx

on Debian 8 live use
cfdisk /dev/sdX