If it's an indicator, an Expert Advisor (EA), or a script, save it to the 'Indicators' folder if it's an EA, save it to the 'Experts' folder and if it's a script, save it to the 'Scripts' folder. To comprehend where to save the EX4 file, you must first comprehend what it is. Once you've arrived, you'll notice a number of subfolders. If you're using MetaTrader 5, for example, you'll see this folder here: The free MetaTrader application from MetaQuotes is used to open EX4 files. To accomplish this, MetaEditor, a tool provided with MetaTrader, is used. The pc code in the EX4 file is created using a MQ4 file, which is a MetaTrader Custom Indicator file. Scripts or indicators used by MetaTrader could be saved in one of these files as well. It's a compiled code system for MetaTrader, a free trading program for the interbank market. The file with the EX4 extension is the MetaTrader Program file. What is an EX4 file, and how can I open one?