An Expert Advisor otherwise known as an EA is a software that runs on the MT4 platform and performs a sequence of trading commands as programmed. Basically, it allows the trader to enter and manage trades automatically without actively placing the trades nor managing them.
It is very important that you study an EA closely before trading with it especially when going to a live as it will be trading while you’re not there.
Also, and 99.999% of the time, the results are false. I’ve been trading for 16+ years and I’ve never seen an EA maintain a consistent profit for months, let alone years.
If trading were that easy everyone would do it. Don’t get fooled into thinking you can do this without putting in the work.
That said, there are many useful EA’s that can assist in trade management and other functions to assist the trader.