President Trump signed an executive order Thursday aimed at loosening some Obamacare requirements so that people can buy less comprehensive, but also less expensive, healthcare coverage, in the wake of the Senate's failure this year to move any legislation to change the law.

"We are all gathered together to do something that is very powerful for our nation and very good for our people," Trump said at the White House, surrounded by officials and small business owners.

The executive order directs the departments of Health and Human Services, Labor, and Treasury to take steps to make it easier for people to band together and buy coverage through what is known as "association health plans." It also would allow people to buy low-cost, short-term health insurance plans, which the Obama administration limited to three months, and would expand the use of health savings accounts. The process will take several months and will not go into effect in time for open enrollment, which runs from Nov. 1 to Dec. 15.

Related: Trump's executive order would mean cheaper insurance premiums for healthy Obamacare customers

Trump was joined by Sen. Rand Paul, R-Ky., who has been discussing the proposal with him for months.

"President Trump is doing what I believe is the biggest free-market reform of healthcare in a generation," Paul said, adding that he believed it would allow millions of people to buy insurance across state lines.

"I want to commend the president for having the boldness and foresight and leadership to get this done," he added.

Trump said he had heard about Obamacare's troubles for many years and noted that Congress, including three Republicans, had blocked a law that would repeal Obamacare. Republicans worked all year to pass a bill that would repeal and replace Obamacare, but failed to gain support within their own party.

The executive order was a way to begin "repeal and replace," Trump said.

"We are starting that process and we are starting it in a very positive manner," Trump said. "When you get Rand Paul on your side it has to be positive, that I can tell you."

The president said that his administration would take more actions on Obamacare in coming months, but did not detail what they would be yet. The push to urge Congress to repeal Obamacare, he said, was not over. He cited a bill known as Graham-Cassidy, which would re-distribute Obamacare's funding and block grants to states so they could craft their own healthcare plans.

As he ended his remarks and prepared to exit the office, and Rep. Greg Walden, R-Ore., told him, "Mr. President, you need to sign it."

"Oh!" Trump said to laughs from attendees.

"I'm only signing it cause it costs nothing," he added.

Related: Mike Pence chases down Trump after he forgets to sign executive order: WATCH

The association health plans proposal mirrors some similarities to a House bill passed earlier this year. One of the bill's supporters, Rep. Virginia Foxx, R-N.C., chairwoman of the House Committee on Education and the Workforce, joined Trump at the signing of the order.

"America's small businesses and the millions of workers they employ are in desperate need of more affordable healthcare options," Foxx said in a joint statement with Rep. Tim Walberg, R-Mich., chairman of the Subcommittee on Health, Employment, Labor, and Pensions, who introduced the bill.

"That's why, earlier this year, the committee approved and the House passed the Small Business Health Fairness Act to empower small employers to band together through association health plans," she said. "We're pleased to see President Trump's leadership on this important effort, and we look forward to working alongside the administration to make association health plans a reality for small business employees across the country."

The order is meant to alleviate high costs for customers who do not receive health insurance coverage from the government or from an employer and whose salaries are too high to qualify them for tax subsidies that lower costs. Many of those customers are facing double-digit premium increases and fewer health insurers to buy coverage from for plans that will take effect in 2018.

Critics of Trump's move have said it would further destabilize the Obamacare exchanges, peeling off healthier people into the less comprehensive plans while leaving an even sicker population with more expensive claims in the exchanges.

Trump previewed the order Tuesday morning and indicated his ongoing frustration with the inability of Republican-controlled Congress to send him a bill that would repeal or overhaul portions of Obamacare.

"Since Congress can't get its act together on Healthcare, I will be using the power of the pen to give great Healthcare to many people — FAST!" he tweeted.