Metatrader is trading software developed by the company Metaquotes.
It offers charting and broker integration through a web application or a windows desktop application.
You can check out the web application with a demo account at their website MQL5.com.
The charting options are very limited. On the desktop application you can load many more indicators, Expert Advisors and even Automated trading tools like robot.
Many brokers use the Metatrader platform as their platform to let you execute trades with them.