I like to hold coins for long term but right now im interested in futures trading
That is spot trading that are talking about.Quote
Lets say i bought long BTC/USD at $47,000 and if bitcoin goes down like at $42,000 will my open order will be canceled automatically without my permission and lose my money.
When you open a long position, it means you are buying a contract where you say that the price will be going up and the exchange accepts that keeping your money aside. If you predict it correctly on a specific time span, you will win the contract and therefore profit. But if your prediction comes out wrong, then you will lose the money or have the keep the contract open for long in which case you need to keep paying liquidation fees to avoid getting your position liquidated.Quote
I know stop limit loss but im not interested at this right now because im always behind my computer.
Are you a zombie? 
Logically speaking, you should have a social life. Making money in trading is not everything. Dont know where you are coming from, but usually people develop bots to track the movements and use smartphones apps to be mobile and trade on the go.
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Also... Can you hold open orders like for a year and if it goes up i take alot of profits..
One phrase : Liquidation fees. This one phrase is the thing that futures traders hate and that is what the exchange will be cutting from your side if you have to keep the position open for a longer period. Quote
My concern is only if im at loss i don't like to sell and lose but im concerned if my open order will be canceled automatically if not set up limit loss and take loss, i always wait for the price to go up at the same price i bought.
You are confusing spot trading with margin trading. You dont sell the position in margin, you open a short/long position.