The Democratic candidate came under attack for her use of a private email account for official business when she served as the top US diplomat.
There were concerns about security and that she may have shielded important facts about her tenure from the public.
Clinton was answering questions after delivering a speech on women's rights at the United Nations on Tuesday. She was speaking for the first time about her email practices as Secretary of State.
She was introduced at the forum as "a future president," prompting applause and cheers throughout the room.
The "vast majority" of her emails," Clinton said, were sent "to government employees at their government email addresses" — which meant they were stored on State Department servers.
Clinton said it was "a matter of convenience." and that she "thought it would be easier to carry one device."
She added: "Using one device would be simpler, but obviously it hasn't worked out this way."
According to the State Department, Clinton was within the boundaries of the law as long as she maintained records of her emails.
State Department officials said that Clinton provided some 55,000 pages of documents — only a small portion of what existed.
The potential 2016 Democratic presidential candidate claims she withheld personal emails — including messages about "Chelsea's wedding plans."
"I feel I've taken unprecedented steps to provide these emails," she said.
On Monday, the White House revealed that President Obama had corresponded with Clinton on her private system, but did not know the system she was using or how it was set up.
Tuesday's question-and-answer session was Clinton's first since the New York Times broke the story of her use of private email more than a week ago.
When questioned whether she or her aides deleted any government emails, Clinton said they did not; instead she believed they erred on the side of providing anything that could possible be viewed as work-related.
She added that the server "contains personal communications from my husband and me" and "the server will remain private".