President Reagan yesterday sent Congress a 37-word proposed constitutional amendment that would permit voluntary prayer in school.

The wording of the amendment represented what one White House aide called the "maximum defensible position" on school prayer and rejected the suggestions of some aides who favored creating "an affirmative right to prayer."

The proposed wording reads: "Nothing in this Constitution shall be construed to prohibit individual or group prayer in public schools or other public institutions. No person shall be required by the United States or by any state to participate in prayer."

Essentially, the amendment would restore the law to what it was before the Supreme Court struck down school-sponsored prayer in classrooms two decades ago. Speaking to advocates of the amendment in the White House Rose Garden on May 6, Reagan urged a reawakening of "America's religious and moral heart" and protection of religion from "government tyranny."

His advocacy of the amendment was a gesture to conservative evangelicals to whom Reagan had promised during the 1980 presidential campaign support for a school prayer amendment.

But in settling on its wording, in language favored by presidential counselor Edwin Meese III and the Justice Department, the president opted for something less than the "affirmative right to prayer" that some of the most militant conservatives advocated.

Theoretically, the amendment proposed yesterday would allow states the option of outlawing school prayers. Reagan opted for a position that an aide described as "getting the federal government out of the business of protecting or invalidating prayer."

Morton Blackwell, a special assistant to the president who is liaison to conservative groups, predicted speedy approval of the amendment by Congress and prompt ratification by the states. Blackwell, who helped draft the proposal, observed that polls showed that three-fourths of Americans supported the amendment despite opposition from a number of religious groups.

"The public expression through prayer of our faith in God is a fundamental part of our American heritage and a privilege which should not be excluded by law from any American school, public or private," Reagan said in a message accompanying the proposed amendment.