passwd is the command used to change the password. In order to change your own password use the command passwd

$passwd

It will prompt you to enter the same password twice.

Moreover, if you wish to change the password of any other user account, specify the username along with the passwd command. Syntax listed below:

#passwd username

Example:
#passwd Saju

Changing password for Saju
(current) UNIX password:
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

Thanks
WintelAdmin