Most brokers trade online in official website, that is, through web pages, which means that you can log in via http and send orders.
If you don't have the ability to analyze the interface, don't worry, there is a ready-made trading framework. Go to github to search for easytrader ~ I used it myself, and it feels good!
Of course, if your broker doesn't have a web trading service, in theory, you can also realize programmatic trading by analyzing the interface of mobile app/ trading software and simulating login, but this may be a little troublesome.