using System;

public class Program

{

    public static void Main()

    {

        var data = "05/29/2021";

        System.Globalization.CultureInfo cultureinfo = new System.Globalization.CultureInfo("pt-BR");

        DateTime dataI = DateTime.ParseExact(data, "MM/dd/yyyy", cultureinfo);

        DateTime myDt = DateTime.SpecifyKind(dataI, DateTimeKind.Local);

        Console.WriteLine(dataI.ToString());

        Console.WriteLine(dataI.ToString("dd/MM/yyyy"));

        Console.WriteLine(dataI.ToString("yyyy-MM-dd HH:mm:ss zzz"));

        Console.WriteLine(myDt.ToString());

        Console.WriteLine(myDt.ToString("yyyy-MM-dd HH:mm:ss zzz"));

        var data2 = "05/29/2021 00:00:00 +03:00";

        DateTime dataI2 = DateTime.ParseExact(data2, "MM/dd/yyyy HH:mm:ss zzz", cultureinfo);

        Console.WriteLine(dataI2.ToString());

        Console.WriteLine(dataI2.ToString("dd/MM/yyyy"));

        Console.WriteLine(dataI2.ToString("yyyy-MM-dd HH:mm:ss zzz"));

​

    }

}