Your $_POST array contains the invite array, so reading it out as
<?php
if(isset($_POST['invite'])){
$invite = $_POST['invite'];
echo $invite;
}
?>
won’t work since it’s an array. You have to loop through the array to get all of the values.
<?php
if(isset($_POST['invite'])){
if (is_array($_POST['invite'])) {
foreach($_POST['invite'] as $value){
echo $value;
}
} else {
$value = $_POST['invite'];
echo $value;
}
}
?>