A tuple allows you to combine multiple values of possibly different types into a single object without having to create a custom class. This can be useful if you want to write a method that for example returns three related values but you don't want to create a new class.
Usually though you should create a class as this allows you to give useful names to each property. Code that extensively uses tuples will quickly become unreadable because the properties are called Item1, Item2, Item3, etc..