How would you go about looping the PDOStatement object named $results and then pass the data to the send_offer function?

<?php
// $results->query("SELECT member_id, email, fullname, level FROM members");

// This is your query but I assume before this you have a pdo object set up
// and you've created an instance of it with $results

// In order to get the results of your query as an associative array from the $results object
// you have to call one of the fetch pdo methods. Either fetch (http://php.net/manual/en/pdostatement.fetch.php)
// or fetchAll (http://php.net/manual/en/pdostatement.fetchall.php)

// As your query doesn't have a WHERE clause I assume you are getting multiple rows so use fetchAll. 
// You do that like this:

$actual_results = $results->fetchAll(PDO::FETCH_ASSOC);

// $actual_results now contains the results of your query as an associative array that you can loop through

foreach ($actual_results as $result) {
    // Now you can do what you want with each row for example:
    echo $result["fullname"];
}

// If you wanted to pass the array of results to your send_offer function you could do that like this:

$foo = send_offer($actual_results);

// You would need to change your function to accept an array instead of individual values though
// I don't understand what it is doing at the moment, I don't think you intend to bindParams inside it?
// You would usually bindParams as part of a PDO stored procedure bit like this:

try {
    $sth = $db->prepare("SELECT * FROM table WHERE col = :param");
    $sth->bindParam(':param', $param, PDO::PARAM_STR);
    $sth->execute();
} catch (PDOException $e) {
    // Error handling here
}
$results = $sth->fetchAll(PDO::FETCH_ASSOC);