Bring a large pot of salted water to a boil. Add the elbow macaroni and cook according to package instructions until al dente. Drain and rinse under cold water to cool.

In a mixing bowl, combine the mayonnaise, apple cider vinegar, Dijon mustard, salt, and black pepper. Mix until smooth.

In a large mixing bowl, combine the cooled macaroni, diced celery, red bell pepper, red onion, and any optional add-ins. Pour the dressing over the salad and mix until well combined.

Cover the salad with plastic wrap and refrigerate for at least 1 hour before serving to allow the flavors to meld.