To show currently mounted partition in human readable format, use:

df -h

Another way to check partition information using parted.

sudo parted /dev/sda print

Here, we can see that the disk size is 120GB along with the partition information.

To view the list of partitions using fdisk, use:

fdisk -l

To view the list of block devices:

lsblk

Hope this helps! Cheers 🙂