The Embassy Office Building at 16th and P streets NW has been sold by Robert H. Richardson for $700,000 to a partnership organized by Jeffrey N. Cohen. Oliver A. Cowan of Snider Bros. Inc. was the broker.

Land recordation and title insurance will be the subjects of a seminar to be held Thursday by the American Land Title Association at the Hyatt Regency Hotel. Among the spekers will be Martin Lobel, a Washington attorney, who will discuss the Torrens system. Reid Paterson, of the Department of Housing and Urban Development's Home Mortagage Section, will give an update on HUD's study of alternative methods of land transfer.

Groundbreaking cremonies for London Woods, a new townhouse community in Capitol Heights, were held this week. The 81-acre site will also offer tennis and basketball courts, picnic and play areas, and hiker-biker trails.

Real estate preparatory courses will be offered by the Arlington Distributive Education Service starting Sept. 16. Satisfactory completion of the course must be submitted with the request for Virginia real estate examination. For information, call 558-2518.

The Northern Virginia Board of Realtors will hold its annual awards luncheon Sept. 29 at Valle's Steak House in Springfield.

A 24-unit apartment house at 1100 F St. NE was sold recently for $185,000 by the C.R.T. parking Co. to Mr. and Mrs. George Jenkins through Ron Chancellor and Stan Marks of Shannon & Luchs.

A trade show for the construction and home building industry will be held Sept. 20 in the Washington Hilton exhibit hall from 3 to 10 p.m. Sponsors are the home builders associations of the District, Northern Virginia and suburban Maryland.

The Porperty Management Association will celebrate its 25th anniversary at its monthly membership meeting Thursday at 6 p.m. at the Ramada Inn in Lanham. Past presidents will be the speakers.