Which type of values can be initialize and declare for different instance variable in C#

All values can be initialised, whether basic types like int and float, or class types like person or order. Value (i.e. basic) types can be initialised with the appropriate values, but class objects need to be initialised by the class constructor, something like:

int i = 10;
float f = 3.14;

person me = new person();
order food = new order();

This should all be explained in your course notes, or see C# Programming Guide | Microsoft Docs[^]