Daniel Cioca  
Hi guys! About Magic Number… I read materials about Magic Number using, but just before I do changes in my EA I would like an opinion. So I have one EA that is opened on each particular pair. I do not use it on same pair twice ( like different timeframes). So in this case, can I remove Magic Number from my code?  Cause I can identify the trade in the code by _Symbol. Thanks! 
William Roeder  

Magic number only allows an EA to identify its trades from all others. Using OrdersTotal/OrdersHistoryTotal (MT4) or PositionsTotal (MT5), directly and/or no Magic number/symbol filtering on your OrderSelect / Position select loop means your code is incompatible with every EA (including itself on other charts and manual trading.)
          Symbol Doesn't equal Ordersymbol when another currency is added to another seperate chart . - MQL4 programming forum (2013)
          PositionClose is not working - MQL5 programming forum (2020.02.21)
          MagicNumber: "Magic" Identifier of the Order - MQL4 Articles (2006)
          Orders, Positions and Deals in MetaTrader 5 - MQL5 Articles 2011

You need one Magic Number for each symbol/timeframe/strategy. Trade current timeframe, one strategy, and filter by symbol requires one MN.