With over 205 million users, Binance is the most widely used Bitcoin exchange in the Democratic Republic of Congo. It's very simple to use and lets you purchase and sell Bitcoin with a variety of payment options. 

Coinbase Exchange holds the second position in terms of trading volume among cryptocurrency exchanges in the USA. As of early 2023, Coinbase has over 89 million verified users across more than 100 countries. 

Another trustworthy exchange with millions of users worldwide is Kraken. It provides a large selection of cryptocurrencies, including Bitcoin, and is simple to use. 

With nationwide availability, Gemini provides a secure and regulated platform for buying and selling crypto. It’s a reliable option for US residents.  As of now, Gemini, is a well-regarded cryptocurrency exchange, serves customers in over 60 countries worldwide. It operates under the regulation of the New York State Department of Financial Services and has gained popularity for its user-friendly interface and commitment to security. 

While primarily a stock trading app, Robinhood also offers cryptocurrency trading. It’s suitable for those looking to diversify their investment portfolio.

OKX supports payments and users from 189 different countries. It's a fantastic option for buying Bitcoin because of its wide assortment of cryptocurrencies. 

KuCoin is a global cryptocurrency exchange that offers spot, futures, margin, and leveraged trading for over 700 coins. With low fees, high security, and 24/7 customer service, it provides a platform for users to buy and sell Bitcoin, Ethereum, and other cryptocurrencies. You can start trading with as little as $1 on KuCoin. If you’re interested, you can sign in to KuCoin and explore their services. They also have a mobile app available on Google Play for convenient trading.