How many days it will require to get visa for tourist visa?

Dear Sir,
I am a Indigenous People from Bangladesh, i
want visit your country, How many days it will require to get visa for
china for tourist visa? Actually I have a Chines friend. He is living
in China. than i want meet with my friend and he also invite to me in
china.

So, What documents i have need to submit to get the visa and minimum
how many days it will take ??

Thanking you
Jeams Chakma
Bangladesh.