My dd command on linux to copy entire disk to img file

sudo dd if=/dev/nvme0n1 of=/mnt/external/hp_elitebook_image/hp_elitebook.img bs=4M status=progress

Before that, you have to find out which disk you want to copy:

lsblk

or

fdisk -l

…and you have to mount external disk where you want to make an img file:

sudo mkdir -p /mnt/external
sudo mount /dev/sdb1 /mnt/external