The so-called, on the modeling industry "polaroid" is a photograph, where the model is not wearing any make up and it has not been re-touched. The term comes from the infamous camera brand "Polaroid", widely used by agencies due to its very convenient ability to produce a photograph in just 3 minutes, which is also 100% original and unmodified.
Every model, who is still unsigned with an agency must have such "polaroids". Most agencies would not even look at any other photographs. Also many casting agencies require models to send polaroids.
You don't have to have a Polaroid camera to take "polaroids" - just use any camera. Simply do this: don't wear any make up and make sure your face is well lit, preferably with natural light; stand straight facing the camera, with absolutely no posing. Take a headshot without a smile; another with a smile, with your teeth visible; and take a full body shot. Turn completely left or right and take another couple shots, similar to the first set. Pick the best four and upload them in your "Polaroids" section on the site.