I'm trying to create a platform to sell cryptocurrencies in my country. the way it works is, the user enters my website, select a coin he wants to buy then the amount he/she wants to buy, he pays in our common currency (say USD) and we should send him/her the cryptocurrency he has bought. the procedure is like most of the crypto shops, but the question is how should I get cryptos to sell? say a user wants to buy 5 Bitcoins, how should I have 5 Bitcoins to give him? how do other websites do this? Any help would be appreciated.
Thanks in advance.