N/file Module
file.File
Object Description: Encapsulates a file within NetSuite. This object only encapsulates a file’s metadata. Content is only loaded into memory (and returned as a string) when you call the File.getContents(). Content from CSV or text files can be accessed line by line using File.appendLine(options) or File.lines.iterator(). Binary content must be base64 encoded. Create a new file.File Object (up to 10MB in size) with the file.create(options) method. After you create a new file.File, you can: upload it to the NetSuite File Cabinet with the File.save() method. attach it to an email or fax without saving it to the File Cabinet. If you want to save the file to the NetSuite File Cabinet, you must set a NetSuite File Cabinet folder with the File.folder property. You must do this before you call File.save(). Returns reader object File.getReader() and iterator of segments File.getSegments(options). For a complete list of this object’s methods and properties, see File Object Members.
Supported Script Types: Server-side scripts For more information, see SuiteScript 2.0 Script Types.
Module: N/file Module
Since: 2015.2
Search NetSuite - https://system.netsuite.com/app/help/helpcenter.nl?search=file.File

// Code Example 1

//Add additional code

//...

var fileObj = file.create({

    name: 'test.txt',

    fileType: file.Type.PLAINTEXT,

    contents: 'Hello World\nHello World'

    });

fileObj.folder = 30;

var fileId = fileObj.save();

//...



//Add additional code



//SOURCE: https://system.netsuite.com/app/help/helpcenter.nl?fid=section_4247974825.html