Most of the U.S. Football League's 600 players have signed cards requesting union representation and they've asked the National Labor Relations Board to certify a bargaining agent, according to the NFL Players Association.

Ed Garvey, executive director of the NFLPA, said he'll meet with Chet Simmons, the USFL commissioner. Garvey said the new union will have its own officers, player representatives and executive committee but will share Washington offices with the Federation of Professional Athletes, an umbrella organization that includes the NFLPA, and player unions for the North American Soccer League and the Major Indoor Soccer League . . .

Janice Williams, wife of quarterback Doug Williams of the Tampa Bay Buccaneers, died in a Louisiana hospital following surgery for a brain tumor. Mrs. Williams, 26, had appeared to be recovering. The Williamses were married last year and had an 11-week-old daughter. They were vacationing in Williams' hometown of Zachary, La. when Mrs. Williams woke up March 30 with a severe headache. A doctor arranged for a brain scan that afternoon. She underwent surgery that night . . .

Attorneys in the NFL antitrust trial in Los Angeles finished their arguments by disputing what the Raiders might have earned if allowed to leave Oakland before the start of the 1980 season.

The same six women who ruled last May the league violated federal antitrust laws by delaying the team's move was prepared to open deliberations in the damage phase of the trial after final instructions from U.S. District Judge Harry Pregerson.

The Raiders, who played in Los Angeles for the first time last season, are seeking $19.9 million in damages and the Los Angeles Coliseum Commission is asking $4.7 million. The cost to the NFL, if the jury rules in favor of team owner Al Davis and the commission, could exceed $70 million; damages in antitrust cases are automatically trebled . . .

The Dallas Cowboys will be the NFL's first team to have a full-time security director, Tex Schramm, the team's president, says. One of the security man's main concerns will be drugs.