sendmatic.js

let Web3 = require("web3");

// Replace value of rpc with https://rpc-mumbai.matic.today for Mumbai
let rpc = "https://rpc-mainnet.matic.network";

const provider = new Web3.providers.HttpProvider(rpc);
const web3 = new Web3(provider);

// Add your private key
web3.eth.accounts.wallet.add("pvt-key");

// Send 10 MATIC
web3.eth
  .sendTransaction({
    from: "your address",
    to: "to address",
    value: web3.utils.toWei("10", "ether"),
    gas: 8000000,
  })
  .then(function (receipt) {
    console.log(receipt);
  });