Here is how to replace the include_blank default text “-Please choose an option-” that is generated when you use the include_blank option in your select. In functions.php you can add a filter to update it.
Edit the Placeholder Text of include_blank in a Contact Form 7 dropdown menu
Add a filter to your theme’s functions.php file
function my_wpcf7_form_elements($html) {
$text_to_replace = '—Please choose an option—';
$new_text = '- Select -';
$html = str_replace($text_to_replace, $new_text, $html);
return $html;
}
add_filter('wpcf7_form_elements', 'my_wpcf7_form_elements');
Be careful with the specific dash character used in the default text, it needs to be coded as — otherwise it won’t recognise the special character.