The 1 Bitcoin is a huge amount of money so we must think many times before we proceed with it as it's hard to earn that money in real life.
Who knows this guy is so damn rich and seems don't care the $6300 that he needs to have to complete his 1 bitcoin.
However, even if it's the case he should be knowledgeable about wallet moreover don't store any funds on exchange sites or any third party wallet.
Anyway, I would suggest OP to be careful in buying bitcoin and don't be impulsive. Try to understand the market first.
So how can I do this through the exchange? So now I need to invest around $6300.
You just need a fiat, lol! Kidding aside, you can link your bank account on any trusted exchange site and just set your buy order.