If an application deadline is on 31 march does that mean I can still apply on 31 or will it close?

sometimes they would allow and extra day and you can explain why the application wasn't turned in by the deadline you would be able to file it say today at the latest tomorrow but you run the risk for them to not except it so i would file it mail it or send it by fax or in person if your still interested in turning it in they depending who processes the application i would have turned it in way before now some would understand if it was not enough time or there was a medical reason that you didn't get to it