Not, EA will not work in case you close Metatrader/computer or if you do not have internet connection of your Metatrader with the broker's server.
MetaTrader 5 Help → Algorithmic Trading, Trading Robots
Traders are using VPS in case they want for their EAs (or signal subscription) to work in case they close Metatrader/computer.
Of course not. Machine and Terminal not running, neither can code.
Leave it on, or run on a VPS. How to Subscribe to a MT4 Signal (new instructions, after 1065 version upgrade) - General - MQL5 programming forum 2017.04.10
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