Most plug-ins that are required for your day to day use of Maya LT are automatically loaded. If you get an error message in the Help line when you try to access a menu item or tool, or if you discover that an expected menu item is missing, this can mean that the feature plug-in is not loaded.
If you suspect there is a plug-in not loaded in your scene, check to make sure the plug-in is loaded using the Plug-in Manager (Window > Settings/Preferences > Plug-in Manager). See also Load or unload Maya LT plug-ins.
For more information on features controlled by plug-ins, see List of plug-ins included with Maya LT.