How can I print window sticker?

While I am not familiar with that type of sticker. I suspect that they take a special process to make. To make something like that yourself may not be possible. There was at one time transparent label material that was nerly invisible when placed on an envelope. If you printed on that type materiial, reversing the image left to right it should look correct when viewed from the other side of a window.

Online labels has some -- http://www.onlinelabels.com/clear-labels?gclid=CPT...

to be very honest you would not be able to make these stickers own your own because they are processed in a special perfect manner and equipments used but if you need these stickers to be printed you may check an online printing company like Sireprinting

Sticker Printing and also get one on my Bike helmet fully custom stickers with high definition printing for fantastic quality and colour.