There are 2 types of automated trading you can do on MT4/MT5 trading platform.

1. Program trading with the opportunity to create your own and use trading programs and indicators created by others. Programs and indicators are created and compiled by means of MQL4 programs built into the MetaTrader4 clients’ terminal.
2. Using signals service, the traders may become a provider of trading signals for other traders and a subscriber to the trading signals from other traders.

You can find more information on their service on the MQL5 official website.