You need an official signature to validate the order.

你要有正式的签字，这张汇票才能生效。

youdao

Here's an example of such a scam using official-looking Bank letterhead and signature.

现举例说明使用看上去正式的世行信笺和签名的诈骗案件。

youdao

With a squiggle of Laura Bo's pen - her signature was usually unreadable - she could make the check official.

劳拉·波只要大笔一挥——她的签字往往是难以辨认的——就可以使这张支票生效。

youdao

He is also accused of forging his wife's signature on official documents.

BBC: Former lieutenant colonel on trial over school fees

At least one road has long been earmarked as suitable for Palestinian safe passage and an official deal on it awaits only the signature of an Israeli prime minister who will honour his word.

ECONOMIST: The Palestinians

The court was told between October 2005 and May 2012 Hart forged official court documents, solicitors' letters and the signature of her employer Philip Desmonde - company director of PDP Green Consultants Limited.

BBC: Swindling secretary Helen Hart jailed