Hi, where you are outputting your text, wrap it in something like this:
<?php if (!get_field('text_input')) : ?>
<h1>I will be hidden if the 'text_input' contains any text.</h1>
<?php endif; ?>
The above will only display the H1 tag if there is no text on the field text_input
in the backend.
Let me know how you get on 🙂