where can i find EA in MT4?
In your MT4, you press tabs"
File -> Open Data Folder -> MQL4 -> Experts
This is the place you should put your Expert Advisers (EAs).
There are many EAs for MT4, for example:
Besides, there are some EAs which pre-installed in your MT4 - look at Navogator wondow of your Metatrader.