QuickTxSample.java

    @Test
    public void sendToSelf() {
        Tx tx1 = new Tx()
                .payToAddress(sender1Addr, Amount.ada(1))
                .attachMetadata(MessageMetadata.create().add("Send to self"))
                .from(sender1Addr);

        QuickTxBuilder quickTxBuilder = new QuickTxBuilder(backendService);
        Result<String> result = quickTxBuilder
                .compose(tx1)
                .withSigner(SignerProviders.signerFrom(sender1))
                .completeAndWait(System.out::println);

        System.out.println(result);
    }

https://preprod.cardanoscan.io/transaction/8889a845d953afcbf8c47fdaa33867b174d3c9c805edb446564ce74472f066f7?tab=metadata