Is it true that a friend recommended me to buy digital currency for transaction on SunCoin platform and only need to pay a deposit to operate? Because this is my first contact
Well, SunCoin doesn't look and sound like a legit marketplace to invest your $10,000 in digital currency.
There are many highly reputable platforms to invest your $10,000 in digital currency such as Binance, Poloniex, BitMex, Kraken, and Bittrex.
That will just be an unnecessary risk he will be taking there using that platform that is not very much popular for such amount of money, the best platform he would have just gone for first is Binance platform, though Binance platform is not very much safe completely too, but just to give them the benefit of doubt after they have been hacked and the promised they have made not to ever allow that to happen again.
If the op is not even going to be into trading, if he is only buying coins for storing it as future investment, maybe in bitcoin, it is best that he buys the coin through Binance exchange and then store it in a private wallet, where he knows that he can have his own private key for proper control and a wallet that will be difficult for hackers to reach.