How do i make a flat texture block ?

Hi, i would like to create a block wish is like. A piece of paper, you can stick it on every block or onto the ground.

The problem is, i can't have a good model. the closest i have came to is the trapdoor type model. But still, it is 3 pixel thick. and everytime we click on it it replaces.

I'm kinda stuck. Any solutions ?