[shanssv]

is there any option to enable/show exit option on home menu?..or how to exit Kodi?

[artfullone]

Add it as a submenu option or reset the skin and you will have a power menu option.

[LloydShow]

Try this.

Settings - Interface - Configure Skin - Customise Home Menu - Add New Home Menu (Plus Icon) - Choose Item For Menu - Kodi Command - Quit

You can also then select "LABEL" and retitle Quit to Exit if you want. Use the up/down arrows on the menu list to place where you wish and done.

[ontap]

Or you could just add the "close kodi " add-on as a main menu item , it is much much better than the default exit option , this add-on closes Kodi instantly without any of that annoying lag you get when using the default exit option . 
Am not gonna post a link to it on here incase its classed as a 3rd party add-on , but if you google "close kodi plugin " you will find it.