// Utxo is: outpoint.txid, outpoint.vout, txout.scriptPubKey, txout.amount
$outpoint = new OutPoint(Buffer::hex('f0768c1159ab868300493e093261c1e78727b389b5c640c78f50fac3eb321d2e'), 0);
$outputScript = ScriptFactory::scriptPubKey()->payToPubKeyHash($privateKey->getPubKeyHash());

$satoshi = 100000000; //one bitcoin in satoshi ie 100 million
$send_wallet_amount = 0.0005425 * $satoshi;
$send = 0.0003520 * $satoshi; // satoshis
$fee = 0.00002 * $satoshi; // satoshis
//calculate change
$change = $send_wallet_amount - $send - $fee;

$txOut = new TransactionOutput($send_wallet_amount, $outputScript);

$transaction = TransactionFactory::build()
    ->input('f0768c1159ab868300493e093261c1e78727b389b5c640c78f50fac3eb321d2e', 0 )
    //->spendOutPoint($outpoint)
    //address to send to
    ->payToAddress($send, (new BitWasp\Bitcoin\Address\AddressCreator)->fromString('bc1qlt95gkn9ufe6z36mgme8nfkjhjavlp79ynjrdz'))
    //change
    ->payToAddress($change, (new BitWasp\Bitcoin\Address\AddressCreator)->fromString('bc1q9pjjydvzyqd8n83znsv6zhh56lk8yztj3m7cjn'))
    ->get();

$tx_hex = $transaction->getHex();

$redeemScript = ScriptFactory::scriptPubKey()->p2wkh($privateKey->getPubKeyHash());
$p2shScript = new P2shScript($redeemScript);
$signData = new SignData();
$signData->p2sh($redeemScript);

$transactionOutputs = [];
foreach ($transaction->getInputs() as $idx => $input) {
    //$transactionOutput = new TransactionOutput(0, ScriptFactory::fromHex($input->getScript()->getBuffer()->getHex()));
    $transactionOutput = new TransactionOutput(0, ScriptFactory::fromHex($p2shScript->getBuffer()->getHex()));
    array_push($transactionOutputs, $transactionOutput);
}
$signer = new Signer($transaction, Bitcoin::getEcAdapter());
foreach ($transactionOutputs as $idx => $transactionOutput) {
    $signer->sign($idx, $privateKey, $transactionOutput, $signData);
}
$signedTx = $signer->get();
$hex = $signedTx->getHex();