The President can’t. The SOTU is mandated by the Constitution, but not described as to how. It could be just a quick letter of a long drawn out speech, but reporting the State of the Union must be done by the President.
a speech is not mandated the president has to report to congress from time to time
He could tweet it every Monday if he wanted to.
The formal basis for the State of the Union Address is from the U.S. Constitution: The President “shall from time to time give to the Congress Information of the State of the Union, and recommend to their Consideration such measures as he shall judge necessary and expedient.” Article II, Section 3, Clause 1.”
George Washington delivered the first regular annual message before a joint session of Congress on January 8, 1790, in New York City, then the provisional U.S. capital. In 1801, Thomas Jefferson discontinued the practice of delivering the address in person, regarding it as too monarchical (similar to the Speech from the Throne). Instead, the address was written and then sent to Congress to be read by a clerk until 1913 when Woodrow Wilson re-established the practice despite some initial controversy. However, there have been exceptions to this rule. Presidents during the latter half of the 20th century have sent written State of the Union addresses. The last President to do this was Jimmy Carter in 1981.[8]
Article II Section 3 Clause 1. This could be once per congressional term, once per presidential term, or once per month.