Hiding files by some sort of software has been a very common way till now, but if you are looking for something different you can do it by hiding a file behind a jpg image.
It is a quite secured way to hide a file behind JPEG image because none will think about the existence of a file inside a jpg image. It is also free from the hazards of installing those software and consequently nobody will notice there is a secret file hidden behind a jpg picture file.
How to hide the files behind JPEG image
copy /b Image.jpg + Secret.rar Image.jpg