WASHINGTON — For decades, presidents have publicly released their tax returns each year — an act of transparency and a way to connect and commiserate with Americans on Tax Day.

On Tuesday, President Trump did not even file his taxes.

White House officials said Mr. Trump, who has steadfastly refused to make any of his previous tax returns public, requested a six-month extension because of the complexity of preparing his 2017 returns. He plans to file by mid-October, officials said.

The announcement came on a day that the president and his allies used to remind people about Mr. Trump’s sweeping tax cuts that will lead to savings for many people when the next Tax Day rolls around in April 2019.

“So many people are seeing the benefits of the Tax Cut Bill,” Mr. Trump tweeted from Mar-a-Lago, his estate in Florida, where he played host to Shinzo Abe, the prime minister of Japan.