Including some variables in function.php and echo them is several place of theme is not working

There are several ways you could do this. As noted above, you can call global every time you want the value:

global $fburl;
echo $fburl;

You can put all your config settings into a single object or array, then put that one object into the globals so it’s available everywhere (doable, but not one I’d choose).

One popular method is to wrap your config settings in a class, then use a getter when you need the value. This assumes that the configuration gets set one time and doesn’t need to be modified on the fly. Here I’m specifically not using the __get() magic method, but creating my own as an example of how it works.

class My_Config {
    private static $config_vars = [
        'fburl' => 'vvv',
    ];

    public static function get_config( $var_name ) {
        if ( array_key_exists( $var_name, self::$config_vars ) ) {
            return self::$config_vars[ $var_name ];
        }

        return null;
    }
}

Now any time you need the value of a defined setting, you’d use (with proper escaping, of course):

echo My_Config::get_config( 'fburl' );