using System;

using Newtonsoft.Json;

class Root

{

    public DateTimeOffset Time { get; set; }

}

​

public class Program

{

    public static void Main()

    {

        var str = "{ \"time\": \"2020-04-13T18:00:00.000+02:00\" }";

        var json = JsonConvert.DeserializeObject<Root>(str);

        Console.WriteLine(json.Time);

    }

}