Display only text to WordPress loop without loosing the text formatting

Try this code in your theme’s functions.php file-

function filtered_content($content){
    $content = preg_replace("/<img[^>]+\>/i", "", $content); // removes images
    $content = preg_replace('/<iframe.*?>/', "", $content); // removes iframes
    return $content;
}
add_filter('the_content', 'filtered_content');

This will remove img and iframe tag from your content. Then use the_content() in your template.