You can use the TextIo X++ class or the CLRInterop. Here are 2 X++ jobs to demonstrate both approaches.
static void Job_TextIO(Args _args)
{
 TextIo textIo;
 #File
 ;
 textIo = new TextIo(@"C:textIOtest.txt", #IO_WRITE, 650001); // textIo([file], [mode], [Encoding])
 textIo.write("Line 1n");
 textIo.write("Line 2");
}
static void Job_StreamWriter(Args _args)
{
    System.IO.StreamWriter sw;
    InteropPermission perm = new InteropPermission(InteropKind::ClrInterop);
    ;
    perm.assert();
    sw = new System.IO.StreamWriter(@"C:test.txt");
    sw.WriteLine("Line 1");
    sw.WriteLine("Line 2");
    sw.Flush();
    sw.Close();
    sw.Dispose();
    CodeAccessPermission::revertAssert();
}
How do i write a txt file using Microsoft Dynamics AX? – Stack Overflow
