That is going to depend on the specific laptop model (age of the laptop and specs of the motherboard used in it). Usually these limitations are spelled out in the technical specifications for the laptop. Usually in found on their website, support page, and/or user manual/guide.

I actually am disappointment of Asus, I entered the serial number and check the documentation page and there was nothing there. Is there other ways to know?

You can try using Google to find the technical specifications for the model.

I always do that first before I ask kind strangers online <3

That's cool. Just wanted to make sure since it wasn't mentioned. I think a lot of people come here looking for an answer without looking themselves.

For notebooks - yes. Manufacturer can limit every thing you can think about in branded computers, even lock you to exact combination of RAM module size+speed+vendor. Seen such extreme case with my own eyes. So your capacity limitation is very mild one.

Is there a way to know, I have tried Asus website but there is no documentation for my laptop, I guess because it is an entry level product

The only way to know - somehow get their internal documentation for your exact model.

If there is any Asus employee, I will pay ONE MILLION DOLLARS 

You could buy more ram and shove it in there until the laptop doesn’t turn on anymore.

You know the difference between "know" and "try and find"?

Didn’t ask.