What is the output of wysiwyg plugins like Summernote and TinyMCE?

Would anyone know to tell me what the output of this type Summernote, TinyMCE, Froala, CKEditor4 publishers is. I looked at the documentation of all these and I did not understand for example how to save the contents in a database for example, I do not know what it generates, if it is an Html, Json, text?

<h1>TinyMCE Quick Start Guide</h1>
<form method="post">
    <textarea id="mytextarea">Hello, World!</textarea>
</form> 

<script>
    tinymce.init({
      selector: '#mytextarea'
    });
</script>