platform = MT4 , the Forex Industry Standart, most brokers use this trading platform
if what you mean are broker, well you need do some research about brokers.
just choose brokers that suitable with your profile.
if you are from UK, better you find a broker with UK regulation
if you dont mind trade offshore brokers, choose the honest one, like Tickmill or HotForex
do your homework, research the regulation, reputation, trading conditions,