The Enable password is used to allow security when an administrator is going from user mode to privileged mode. It is used to protect privileged mode on equipment which is not physically secured. The Enable password is an old, non-encrypted command that should not be anymore in use (password it is stored in startup-config file non-encrypted).
Newer versions of IOS have replacement command enable secret. When secret is enabled (activated), password command is automatically inactive, and secret is in use.
Command is: enable password yourpassword
Press RETURN to get started.
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#enable password password1
%SYS-5-CONFIG_I: Configured from console by console
Router#copy running-config startup-config
Destination filename [startup-config]? ENTER
Password can be seen in startup-config, for example:
enable password password1