Please add the below code snippet in your child theme’s functions.php file to achieve your requirement.
add_filter('woocommerce_form_field_hidden', 'th_woo_form_field_hidden', 11, 4);
function th_woo_form_field_hidden($field, $key, $args, $value){
if(is_null($value) || (is_string($value) && $value === '')){
$value = $args['default'];
}
if (isset($key) && $key == '<strong>field_name</strong>') {
date_default_timezone_set('<strong>Asia/Kolkata</strong>');
$value = date("h:i:sa");
}
$field = '<input type="hidden" id="'. esc_attr($key) .'" name="'. esc_attr($key) .'" value="'. esc_attr( $value ) .'" class="'.esc_attr(implode(' ', $args['class'])).'" />';
return $field;
}
Replace field_name with your hidden field name and Asia/Kolkata with your corresponding timezone.
Thank you!