How to remove admin menu in wordpress ?

Use the below code

function wpexplorer_remove_menus() {
 remove_menu_page( 'themes.php' );          // Appearance
 remove_menu_page( 'plugins.php' );         // Plugins
 remove_menu_page( 'users.php' );           // Users
 remove_menu_page( 'tools.php' );           // Tools
 remove_menu_page( 'options-general.php' ); // Settings
}
add_action( 'admin_menu', 'wpexplorer_remove_menus' );