Assuming your sd card is /dev/sda (check with lsblk):
sudo umount /dev/sda*
sudo parted -s /dev/sda mklabel msdos -- mkpart primary ext4 16MiB -1s
sudo mkfs.ext4 /dev/sda1
Assuming your sd card is /dev/sda (check with lsblk):
sudo umount /dev/sda*
sudo parted -s /dev/sda mklabel msdos -- mkpart primary ext4 16MiB -1s
sudo mkfs.ext4 /dev/sda1