In C# commonly use DTO classes for data transfer. But also we can transfer data using Entity Framework generated class. But most of the time we uses DTOs to transfer data. Why DTOs needs to pass data across layers instead of using Entity Framework generated classes.
I think one reason, using dto classes does not directly bind the client to your database model, as it would if you were transferring ef classes. It allows you to make changes to your backend and in some cases keep these changes from effecting your clients. There are truly many more reasons, I think doing some research on the net will help more perhaps, there are many fantastic articles. However you will have to decide whether the use of dto classes fit into your current project. Some people say dto classes are bad and they go in depth to explain why they say so, others say the opposite and again explain why they say so. You will need to determine which is best for the task at hand. Overall I think answers for this question would be opinion dependant. Personally, I love dto classes.