buying and selling in low quantity

hello,

I'm new to investing, i've been reading about the different kinds of securities that exist, and when i was reading about options, i got a doubt about buying stocks.

Is it easy/fast to buy/ sell stocks in low quantity?

EX: There is a order in the market to sell 100 shares at 20$. I wanna buy 30 shares at 20$. Is there a possibility to buy 30 shares out of the 100 shares order, or do i have to buy the total quantity of the order? (I know that is fully automatic process that my online broker does, its just to try to understand the process).

Sorry for the bad english translation, im asking this because i want to know how does it work to buy low volume of shares.

Thanks for the response!

Submitted January 07, 2019 at 09:50AM by tomasreis98 http://bit.ly/2VAP124