stock trading can take place through the stock broker. stock brokers connect us to exchange and trade take place.the order can be placed through the broker from out trading account provided by the stock brokers .the types are long , short , long unwinding , short covering , future buy , future sell call and put option . validity is based on the order and also by the stoploss.long- trade buyat low price short- sellect high price long unwinding – in the long selling shares is the long unwindingshort covering – it the short buying of shares .positional treading is a long time treading for eg:weaks , money if no way affects the performance of the company. below stock price is determined only by the buyer and seller.