How to access data passed to views and pages

I am trying to pass data to my blade views. Normally, in laravel you would just pass the data along with the view that you are calling to display.

In sage, as far as I understand you add a filter in app\filters.php.
An example is shown in the code block in this doc

But my question is… How to I access/reference the data from my blade templates. For example

add_filter('sage/template/page/data', function (array $data) {
    $data['header_image'] = get_field('header_image');
    $data['header_content'] = get_field('header_content');
    $data['key'] = 'VALUE';
    return $data;

In my blade template I have tried {{$data[‘key’]}} {{$key}} {{$data->key}}… None of these work… None of these output ‘VALUE’ on my page.

You seem to be doing things correctly, so you may be running into the issue mentioned in this post: Sage 9 - Passing ACF data via Blade not working

Yes. That worked. Thanks. Sorry for duplicate.