President Reagan opens his fall campaign for tax revision with a speech in Independence, Mo., at a festival commemorating pioneer days. The president will return to Washington tonight. TUESDAY

Health and Human Services Secretary Margaret M. Heckler holds an 11 a.m. news conference in the auditorium of the Humphrey Building to make an announcement on generic drugs. Education Secretary William J. Bennett teaches an 11th grade history class at Banneker High School in the District. WEDNESDAY

The House returns from its recess; the Senate returns next Monday. Linda Chavez, deputy assistant to the president and director of the Office of Public Liaison, will discuss Reagan's agenda at a luncheon sponsored by Women in Government Relations. The event will be held in the Crystal Room of the Sheraton-Carlton Hotel; Chavez' talk will begin about 1 p.m. The National Association of Towns and Townships holds its annual conference at the Sheraton Washington Hotel. FRIDAY

The Office of the Federal Register sponsors a workshop, "The Federal Register: What It Is and How to Use It," beginning at 9 a.m. in the conference room of 1100 L St. NW. Phone 523-5239. The Full Employment Action Council holds an 11 a.m. briefing on "Economic Dislocation and Structural Unemployment: The Plight of America's Basic Industries." The session will be in Room 2175 of the Rayburn House Office Building.