Difference when initializing values of a class?

I have a class with too many variables, I need to initialize the values empty depending on the type of data, I see that I can do it in two ways:

public class Documento
{
    public Document()
    {
        Tipo = "";
        Numero = "";
    }

    public string Tipo { get; set; }
    public string Numero { get; set; }
}

and in this other way:

public class Documento
{
    public string Tipo { get; set; } = "";
    public string Numero { get; set; } = "";
}

What is the difference?