Getting value of text field in controller?

Question

Magento 2.3

I added a new text field to review.phtml, it looks like that:

<input type="text" id="tel" name="pptel" /> 

Now in my controller I am trying to get that value, like this:

$this->getRequest()->getParam('pptel');

Does not work, also $_POST and $_GET are empty. I guess the new field value is just not added to the request, but why? How would I do that?

Thanks