using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Text;

public class MemoryRead
{
    const int PROCESS_ALL_ACCESS = 0x1F0FFF;

    [DllImport("kernel32.dll")]
    public static extern IntPtr OpenProcess(int dwDesiredAccess, bool bInheritHandle, int dwProcessId);

    [DllImport("kernel32.dll", SetLastError = true)]
    static extern bool WriteProcessMemory(int hProcess, int lpBaseAddress, byte[] lpBuffer, int dwSize, ref int lpNumberOfBytesWritten);

    public static void Main()
    {

        Process process = Process.GetProcessesByName("notepad")[0];
        IntPtr processHandle = OpenProcess(PROCESS_ALL_ACCESS, false, process.Id);

        int bytesWritten = 0;
        byte[] buffer = Encoding.Unicode.GetBytes("It works!\0"); // '\0' marks the end of string

        // replace 0x0046A3B8 with your address
        WriteProcessMemory((int)processHandle, 0x0046A3B8, buffer, buffer.Length, ref bytesWritten);
        Console.ReadLine();
    }
}