These tutorials use various Web3 libraries to send transactions on the Goerli testnet. The demo-eth-tx repository contains additional scripts to send regular transactions or contract transactions using Web3 or Ether.js.
You can also use Infura Transactions (ITX) to send Ethereum transactions. ITX handles all edge cases for transaction delivery and takes care of getting transactions mined while removing the need for developers to deal with the complexities around gas management.
You can use MetaMask or similar to create an Ethereum account for testing purposes.
Use a faucet to load testnet ETH on your Ethereum account for the Goerli network.