How to Use Options in Passwd Command

All linux command has the same structural syntax writing

command [-options] [attr]

and passwd is not else

passwd [options] [LOGIN]

So for example I'm gonna list some uses of options

Delete(make it empty) an account password using the -d option

$ sudo passwd -d guest

passwd: password expiry information changed.

Now for your case above first you dont' use sudo and also be sure of using correct user name Madhu G? Since I dont think that you can have a username with space between

Another Example expire the account password using -e option

$ sudo passwd -e guest

passwd: password expiry information changed.

Your command is wrong.

passwd -d Madhu G

passwd accepts this:

passwd [options] [LOGIN]

Your command deviates from this requirement and, therefore, a list of possible parameters will be displayed:

$ passwd -d Madhu G  
Usage: passwd [options] [LOGIN]

Options:
  -a, --all                     report password status on all accounts
  -d, --delete                  delete the password for the named account
  -e, --expire                  force expire the password for the named account
  -h, --help                    display this help message and exit
  -k, --keep-tokens             change password only if expired
  -i, --inactive INACTIVE       set password inactive after expiration
                                to INACTIVE
  -l, --lock                    lock the password of the named account
  -n, --mindays MIN_DAYS        set minimum number of days before password
                                change to MIN_DAYS
  -q, --quiet                   quiet mode
  -r, --repository REPOSITORY   change password in REPOSITORY repository
  -R, --root CHROOT_DIR         directory to chroot into
  -S, --status                  report password status on the named account
  -u, --unlock                  unlock the password of the named account
  -w, --warndays WARN_DAYS      set expiration warning days to WARN_DAYS
  -x, --maxdays MAX_DAYS        set maximum number of days before password
                                change to MAX_DAYS

Correct syntax, but still wrong because with space and not lowercase:

sudo passwd -d "Madhu G"

For your account (bad idea)

sudo passwd -d "$USER"

or for another login name (without spaces and with lowercase):

sudo passwd -d <username>