Text field in frontmatter/header without blueprint

I like to add a text field in the header/frontmatter, so that i can use it anywhere in a connected twig something like

in the .md:

 ---
 title: Service
 menu: Service
 subtext: any text here
 ---

in the twig:

<div class="aclasshere">
    <p>{{ page.header.subtext }}</p>
</div>

or for more text

subtexts: 
      txt1: any text here
      txt2: anymore text here

{{ page.header.subtexts.txt1 }}

Is this not possible? Obvoiusly am I getting something wrong with the fields... 😦

Are you talking about creating a fillable text field in the Admin interface? In that case, I can't help you (I don't use the Admin module), but I'm pretty sure you need a blueprint for that.

Otherwise, you can obviously just edit the Markdown files directly to add data to the front matter or use something like the Import plugin to pull in external data. You can also put "global" front matter in the site or theme config files.

Thanks Perlkoenig for the hint,
I just wanted to add text at a certain position, and i wondered if i have to declare the fieldname anywhere (without using a blueprint file) before using it OR if i could use any fieldname in the frontmatter of the Markdown without declaring it anywhere before like

subtext: any text here
and in the twig-file
{{ page.header.subtext }}

It looks to me that this is possible and it worked now after a lot of reloads and refreshs