set fso=createobject("scripting.filesystmeobject")
set fptr=opentextfile("c:\sample.txt",2,true)
fptr.writeline("this is sample program")
set fptr=nothing


in this 2 for write mode and true for if file doesn't 
exist, it can create a new file sample.txt, if we give 
false, it can open the file sample.txt which is already 
exists.

the above answer is not correct

sline="Hello"
Set fso = CreateObject("Scripting.FileSystemObject") 
Set CreateFile = fso.CreateTextFile("c:\x1.txt",True)
CreateFile.close
Set OpenFile = fso.OpenTextFile("c:\x1.txt",8,True)
OpenFile.Writeline sline
OpenFile.Close

I thik This Code will Work

set a=createobject("wscript.shell")
a.run "Notepad.exe"
Set Obj = Window("regexpwndtitle:=  Notepad").WinEditor
("nativeclass:= Edit")
Obj.Click
a.Sendkeys "I Love QTP"

Dim a,b
Set a= CreateObject("Scripting.FileSystemObject")
Set b= a.CreateTextFile("c:\Test.txt")
b.Writeline("Hi Welcome To QTP")