Если поле заполнено ACF
<?php if( get_field('field_name') ): ?>
<p>My field value: <?php the_field('field_name'); ?></p>
<?php endif; ?>
Better Bird
<?php if( get_field('field_name') ): ?>
<p>My field value: <?php the_field('field_name'); ?></p>
<?php endif; ?>