A review into her emails revealed she had used her private address to contact government officials.
Ms Trump sent the emails before she was briefed on the rules, her lawyer says.
In 2016, her father Donald Trump accused Hillary Clinton of putting the US “in danger” over her use of a private email while secretary of state.
Ivanka Trump sent hundreds of emails last year to White House aides, Cabinet officials and her assistants using a personal account, many of them in violation of federal records rules, according to people familiar with a White House examination of her correspondence.
White House ethics officials learned of Trump’s repeated use of personal email when reviewing emails gathered last fall by five Cabinet agencies to respond to a public records lawsuit. That review revealed that throughout much of 2017, she often discussed or relayed official White House business using a private email account with a domain that she shares with her husband, Jared Kushner.
The discovery alarmed some advisers to President Trump, who feared that his daughter’s practices bore similarities to the personal email use of Hillary Clinton, an issue he made a focus of his 2016 campaign. Trump attacked his Democratic challenger as untrustworthy and dubbed her “Crooked Hillary” for using a personal email account as secretary of state.
Some aides were startled by the volume of Ivanka Trump’s personal emails – and taken aback by her response when questioned about the practice. Trump said she was not familiar with some details of the rules, according to people with knowledge of her reaction.
The White House referred requests for comment to Ivanka Trump’s attorney and ethics counsel, Abbe Lowell.
In a statement, Peter Mirijanian, a spokesman for Lowell, acknowledged that the president’s daughter occasionally used her private email before she was briefed on the rules, but he said none of her messages contained classified information.
“While transitioning into government, after she was given an official account but until the White House provided her the same guidance they had given others who started before she did, Ms. Trump sometimes used her personal account, almost always for logistics and scheduling concerning her family,” he said in a statement.
A Trump administration official told CBS News that Ms Trump’s emails did not contain classified information, and what had occurred was basically a lack of understanding of the rules.
Ms Trump stopped using her personal address for government correspondence after she was informed that she should not be doing so, the official said.
However Austin Evers, from a group called American Oversight, which submitted the freedom of information request that led to the discovery of Ms Trump’s use of personal email last year, said the “president’s family is not above the law”.
“There are serious questions that Congress should immediately investigate,” Mr Evers said in a statement.
“Did Ivanka Trump turn over all of her emails for preservation as required by law? Was she sending classified information over a private system,” he added.
Are private emails illegal?
It is not illegal for White House officials to use personal email accounts for government business.
However, under the Presidential Records Act and Federal Records Act, government officials must forward any official correspondence to a work account within 20 days for preservation.
If this is not done reliably, the use of private accounts can put official records beyond the reach of journalists, lawmakers and others who seek publicly available information.
There are also rules against sharing classified or privileged information on personal email accounts.