The chairman of the House Oversight and Reform Committee revealed information on Thursday that he said showed that Ivanka Trump and Jared Kushner used private email accounts and a publicly available messaging service for official White House business in a way that possibly violated federal records laws.

A lawyer for Ms. Trump, President Trump’s daughter, and Mr. Kushner, the president’s son-in-law and senior adviser, told the committee late last year that in addition to a private email account, Mr. Kushner uses an unofficial encrypted messaging service, WhatsApp, for official White House business, Representative Elijah E. Cummings of Maryland, the committee’s chairman, revealed. That business includes foreign contacts, the lawyer, Abbe D. Lowell, told the committee.

Mr. Cummings said Mr. Lowell also told the committee that Ms. Trump did not preserve some emails sent to her private account if she did not reply to them.