William H. Jones, deputy financial editor of The Washington Post and editor of the Washington Business section, will become director of corporate affairs for Potomac Electric Power Co. effective April 1.

Jones will succeed Pepco's David Boyce, who has resigned to return to Bell Laboratories in Short Hills, N.J., where he was manager of public relations before joining the Washington utility. Boyce will become head of management communications for Bell Laboratories to handle the impending breakup of the American Telephone and Telegraph Co.

As Pepco's new public affairs chief, Jones will be responsible for advertising, media relations, employe communications, community relations and educational services.

Jones left the New York Times News Service in 1967 to join the Los Angeles Times/Washington Post News Service. Two years later, he moved to The Post's financial section.

As deputy financial editor, Jones has been responsible for The Post's coverage of local business news, wrote a column on area economic affairs and launched the Monday Washington Business section. Washington Business was one of the first newspaper sections devoted to local business coverage and the concept has been widely copied by other newspapers.

A native of Baltimore, Jones is a graduate of Syracuse University and studied in Australia as a Fulbright scholar.

Lois Reed Munday will succeed Jones as editor of Washington Business. Munday joined The Post's financial staff three year ago from The Dallas Times Herald and has served as assistant editor of Washington Business and financial news assignment editor.