There are over 1100 hotels in the city of Venice. Because everyone books accomodation online these days, on website with endless helpful reviews, you won't find any hotels on this app. Just check out listings on Booking.com, or Hostelbookers and Hostelworld (for cheaper choices and campsites).
Venice is one of the most expensive cities in Italy, especially in high season (from Easter to October), or during Carnival or other major festival or event, and getting around can also do serious damage to your bank account. Unless you have the readies to take a boat taxi to the door of your hotel, consider too how far you'll have to walk from the nearest vaporetto stop. Hauling luggage up and down the bridges isn't much fun.
Image by Galileo~commonswiki; Hotel Danieli