Herbert W. Armstrong, 93, the founder of the 80,000-member Worldwide Church of God and an evangelist who made wide use of radio, television and magazines, died Jan. 16 at his home here. The cause of death was not reported, but he had had heart ailments over the years.

The church's financial support made it a powerful evangelistic organization. The Plain Truth and Quest magazines and "The Ambassador Hour" television show are part of Mr. Armstrong's legacy. Church publications are printed in several languages and the television show is seen widely in syndication. The church also founded Ambassador College here.

The Worldwide Church of God was started 53 years ago as the Radio Church of God. It is based on fundamental teachings of both the Old and New Testaments and incorporates several tenets of Judaism. In its theology, Mr. Armstrong was the appointed apostle of Jesus Christ on earth.

Joseph K. Tkach, director of church administration for the past six years, was designated earlier this week to follow Mr. Armstrong as head of the Pasadena-based church.

Until a falling out in 1978, the church's television spokesman for many years was Mr. Armstrong's son and heir-apparent, Garner Ted Armstrong. The younger Armstrong has conducted an independent ministry since then.

In their dispute, the elder Armstrong accused his son of trying to take over the church. Garner Ted Armstrong and a group of former church members alleged that Mr. Armstrong and then-treasurer Stanley Rader had spent $70 million in church funds on personal expenses.

In 1979, the California attorney general's office conducted a review, and a court-appointed receiver took over church affairs. In October 1980, the case was dropped after the legislature passed a law barring the attorney general from investigating religious organizations accused of misuse of funds or internal civil fraud.

Mr. Armstrong made headlines again in 1984 when he was divorced from his 45-year-old secretary after a two-year court battle.