My teacher ask me to bring for the next lesson something similiar to MDF board but what's that ?! I thought that this is a wooden board that you put under your paper while u draw , is that right ?!

It could be used for that. Some painters of oils use it as a base for their paintings. Are you taking a drawing class? Do you have a drawing board?

this week we will have drawing classes and they told us to bring mdf A1, (Im doing Foundation Degree in art and design)

MDF or medium density fiberboard could be used as a drawing board or also for painting. It's made up of very small fibers similar to that used in cardbord bound together with waterproof resins and glue. We use it quite a bit in cabinetmaking when a high gloss paint finish is wanted with no wood grain showing through.

Hope this helps
Jim

Did you get a specification? A1 size is 594 x 841mm, I would suggest a minimum thickness of 6mm, but recommend 9mm for dimensional stability. You should able to get this from any DIY store or timber merchant. Check the piece you're buying for a smooth surface, last thing you need is a few indentations.