Add text with a link after the LearnDash login modal heading.

functions.php

<?php
/**
 * Add text with a link after the LearnDash login modal heading.
 */
function kanuka_add_text_after_login_modal_heading() {
	?>
	<div class="my-custom-text">
		<p>This is some additional text. <a href="https://example.com">Click here</a> for more information.</p>
	</div>
	<?php
}
add_action( 'learndash-login-modal-heading-after', 'kanuka_add_text_after_login_modal_heading' );