Here's a trick to hide your text in the window's default text editor i.e. Notepad using Command Prompt :)
but this trick works only on NTFS File System.

Steps:

1. Open Command Prompt. Start--> Run and type cmd.
2. Now goto your desired  location where you want to have your file saved. Lets say Desktop then type cd desktop and enter.
3. Now type in Command Prompt the following lines.notepad anyname.txt:hidden 
   
   
   
   
   
4. Now type your data and save(Ctrl+S) the file.
5. Browse to the file location and Open anyname.txt, you will not be able to see any data.
6. To retrieve the hidden data open Command Prompt and type the same command notepad anyname.txt:hidden