The demand arrived at 4:28 p.m. Eastern time on Valentine’s Day.

“The US government only recognizes two sexes: Male and Female. This needs to be changed immediately,” the popular right-wing account Libs of TikTok posted on X, the social media platform owned by Elon Musk.

The missive, blasted to the account’s 4.2 million followers, was accompanied by screenshots of the Free Application for Federal Student Aid, the government form that determines eligibility for financial assistance in paying for college or trade school. It allowed students to identify as “nonbinary” or select “prefer not to answer” when asked to select their gender.

The account for Mr. Musk’s so-called Department of Government Efficiency replied five hours later with screenshots of the updated form: “Fixed.”

As his operation targets spending considered unaligned with President Trump’s agenda, Mr. Musk has personally appealed to users of his social media platform to help root out what he has termed “waste, fraud and abuse.” He has been responsive to complaints from accounts that go viral, with his team trumpeting the apparent changes pushed through as a result. And for at least two prominent conservative activists, a Trump administration so carefully attuned to right-wing social media has created the opportunity to build an extraordinary pipeline of influence and access.

In multiple instances, viral posts by Chaya Raichik, who is the creator of the Libs of TikTok account and regularly attacks transgender people online, and Christopher Rufo, a writer who has worked to push conservatives further right on education issues, have prompted quick adjustments to public-facing government documents and even policy. Most of their efforts have centered on the Education Department, which Mr. Trump has said he wants to eliminate, though other agencies have become targets, too.