In his testimony, Mr. Zuckerberg is expected to promote the benefits of Libra. He plans to describe Libra as a democratizing financial system that will mostly benefit the poor, as well as the estimated 14 million people in the United States who do not have access to bank accounts and who cannot afford banking fees.

“People pay far too high a cost — and have to wait far too long — to send money home to their families abroad. The current system is failing them,” Mr. Zuckerberg said in the advance version of his testimony. “The financial industry is stagnant and there is no digital financial architecture to support the innovation we need. I believe this problem can be solved, and Libra can help.”

Facebook’s cryptocurrency project is the latest controversy to draw Mr. Zuckerberg to Washington.

Last week, he delivered a manifesto on free expression at Georgetown University, defying requests by Democratic politicians to take down false and misleading information by political leaders. Weeks earlier, he met with President Trump and Republican lawmakers to beat down accusations that Facebook gives priority to liberal-leaning content.

The House hearing will be the second time Mr. Zuckerberg has testified on Capitol Hill. In 2018, he was asked to respond to claims that the company did not properly handle its users’ data and had not treated privacy concerns with seriousness.

A few weeks after Libra was unveiled, Maxine Waters, Democrat from California and chairwoman of the House Financial Services Committee, led several lawmakers in a call for Facebook to stop the project until it was vetted by lawmakers and regulators. David Marcus, the Facebook executive in charge of Libra, appeared before Ms. Waters’s committee in July, but he appeared to make little progress toward détente with the lawmakers.