WASHINGTON—President Donald Trump signed an executive order Tuesday to help accelerate long-delayed efforts to modernize the government’s patchwork of aging computer systems.

It’s one of a series of steps, led by senior adviser Jared Kushner, that the administration is expected to take to speed up the slow process.

The federal government spends as much as $90 billion a year on information technology, but much of that money is wasted on maintaining costly and duplicative legacy systems that are often 10 to 20 years out of date, according to critics on both sides of the aisle.

One reason is a lack of funds for modernizing the government’s massive technology infrastructure. But another reason is the highly fragmented system that many agencies have traditionally used to oversee their IT.

For example, many agencies have numerous chief information officers, not just one, to run their IT. Those CIOs often don’t report to agency heads or coordinate effectively, and they sometimes have little incentive or authority to implement comprehensive modernization plans, administration officials said.