From http://www.w3schools.com (Copyright Refsnes Data)

ASP WriteLine Method

The WriteLine method writes a specified text and a new-line character to a TextStream file.

Syntax

TextStreamObject.WriteLine(text)

Parameter	Description
text	Optional. The text to write to the file. If you do not specify this parameter, a new-line character will be written to the file

Example

<%
dim fs,f
set fs=Server.CreateObject("Scripting.FileSystemObject")
set f=fs.CreateTextFile("c:\test.txt",true)
f.WriteLine("Hello World!")
f.WriteLine("How are you today?")
f.WriteLine("Goodbye!")
f.close
set f=nothing
set fs=nothing
%>

The file test.txt will look like this after executing the code above:

Hello World!
How are you today?
Goodbye!

Complete TextStream Object Reference