ETH can be easily exchanged/converted to any other Ethereum based tokens (e.g. DAI, USDC, OXT, BAT, etc.) by using a really convenient, quick, and easy to use Ethereum blockchain application called Uniswap.
You will need to have already setup your MetaMask wallet and have some ETH on it to be able to exchange ETH on Uniswap. If you haven't already setup your MetaMask wallet or don't know what MetaMask is or why you need it, please visit: FAQ, MetaMask, before continuing.
Go to the Uniswap application website at: Uniswap Exchange. Once there, you will be presented with the following simple but nice looking interface; which, has three options: "Swap", "Send", and "Pool". For this example we are going to only used the "Swap" option to convert some ETH to DAI. Make sure MetaMask is unlocked, then press on the big "Connect to Wallet" button at the bottom of the page to connect MetaMask with Uniswap.
After pressing on the "Connect to Wallet" button a new window menu is displayed showing you the types of Ethereum wallets that Uniswap currently supports, press on the "MetaMask" button to continue.
A new window will be displayed asking you for permission to connect Uniswap with MetaMask, press on the "Connect" button at the bottom right corner to allow the connection.
Once you have allowed Uniswap to connect to MetaMask, and if the connection is successful, a new window showing your public MetaMask address will be displayed. Press on the "X" button at the top right corner to continue.
Now you are presented with the initial Uniswap window but with your MetaMask wallet connected to it, press on the "Select a token" button to select the desired token to exchange ETH to.
Type or search for the name of the token, since we are going to exchange ETH to DAI in this example we can just type "DAI" on the search bar and press on its button once it is displayed, like this:
After selecting "DAI", on the previous window, now you can begin the exchange process. Enter the desired amount of ETH to exchange to DAI in the "Input" text box, and press on the "Swap" button.
A confirmation window will then be displayed, verify that everything is as it should and press on the "Confirm" button to start the exchange process.
MetaMask will show you a notification, once the exchange process is finished.