So let's break it down the 90 days before looking at the 180-day part: You're allowed to visit the Schengen Area for a maximum of 90 days within every 180 days.
Those using , will be notified by their support team if any extra document is required during the application process.
You will also need to carry two photographs, a few other important documents, a confirmed return ticket and proof that you will be able to pay for your trip and stay in Singapore.