If you prefer self-custody, you can swap tokens directly from your wallet without a middleman. Google's Finance Data
Place a (for instant execution) or a Limit Order (to buy at a specific price). buy btc with eth
Create and verify an account on a platform like Kraken, Coinbase, or Binance . Deposit your ETH into the exchange wallet. Locate the trading pair. If you prefer self-custody, you can swap tokens