Example with a 20TB Western Digital drive:

sudo su
lsblk
# For me it's definitely /dev/sda, confirmed.
parted /dev/sda
print
mklabel gpt (if prompted, type in "yes")
mkpart primary ext4 1MB 20TB
print
quit

Next, format it:

mkfs -t ext4 /dev/sda

Mount the drive and check the space: