Calling method from C# dll

Question

how could i call a static method from a dll (wrote in c#) from my main program (also wrote in C#)?

public static class Entry
{

    [DllImport("User32.dll", CharSet = CharSet.Unicode)]
    private static extern int MessageBox(IntPtr h, string m, string c, int type);
    
    // method which needs to be called
    public static void init()
    {
        MessageBox((IntPtr) 0, "Executed", "Working.", 0);
    }
    
}

Thats the dll.

    public static void Main(string[] args)
    {
        var dll = Assembly.LoadFile(@"C:\Users\User\Desktop\mydll.dll");

        foreach (var type in dll.GetExportedTypes())
        {
          // how to call the 'init()V' method without creating an instance?
        }
    }

Thats the executable.

Both the exe and the dll are wrote in the same .net version (4.5).

If i would like to obfuscate my dll, how could i get the init method after it got renamed?

Thanks.