WASHINGTON—Federal laws and regulations on preserving government records only recently have begun to catch up with how U.S. officials communicate, a fact highlighted by the public stir over Hillary Clinton’s private email use as secretary of state.

The Federal Records Act requires government agencies to preserve records documenting the “organization, functions, policies, decisions, procedures and essential transactions” of an agency’s business. But it was only last year that Congress passed, and President Barack Obama signed, a law with a series of modern-day changes to improve recordkeeping and preservation.

The 2014 overhaul, which postdates Mrs. Clinton’s tenure at the State Department, placed explicit limits on agency officials using private email accounts for official business. The new law said agency officials can’t create or send a government record on a private account unless they also copy or forward the email to their official government email address.

The National Archives and Records Administration in September 2013 issued guidance to federal agencies that said federal employees generally shouldn’t use personal email accounts to conduct official business, except in limited situations, such as during emergencies when an official may not be able to access an official account.

That 2013 guidance, which also postdated Mrs. Clinton’s tenure, replaced a 2008 memo on federal recordkeeping that didn’t specifically address email records.