Senario: when i upload the file ,its saves in my personal Document 
But my Requirement is it should be saved in Different folders name/separate Name
eg:SMS Imgica,Read in india etc.

Hey guys please give me solution for below code:

public with sharing class ctrlDocumentInfo 
{
  public String FolderName {get;set;}
    public String folder { get; set; }

    public ctrlDocumentInfo()
  {FolderName = '';
 }
public Document document {
    get {
      if (document == null)

        document = new Document();

      return document;

    }
    set;
  }
  
    public List<SelectOption> getAttFold() 
    {
    List<SelectOption>lstfold = new List<SelectOption>();
   for(folder objFolder:[select id,name from folder where type='document' ]){
 lstfold.add(new SelectOption(objFolder.id, objFolder.Name));
}
    return lstfold;
  }

public PageReference upload() 
{
    document.AuthorId = UserInfo.getUserId();
    //Folder f=[SELECT Id,Name FROM Folder WHERE Folder.Name = 'SMS Magic' ];
    document.FolderId = UserInfo.getUserId(); // put it in running user's folder
   // document.folderId = f;
    try {

      insert document;

    } catch (DMLException e) {

      ApexPages.addMessage(new ApexPages.message(ApexPages.severity.ERROR,'Error uploading file'));

      return null;

    } finally {

      document.body = null; // clears the viewstate

      document = new Document();
    }
    ApexPages.addMessage(new ApexPages.message(ApexPages.severity.INFO,'File uploaded successfully'));

    return null;

  }
}