WASHINGTON — President Biden is expected to sign an executive order on Sunday that directs the government to take steps to make voting easier, marking the 56th anniversary of the Bloody Sunday march in Selma, Ala., which swiftly turned voting rights into a national cause.

The multipart order is aimed at using the far-flung reach of federal agencies to help people register to vote and to encourage Americans to go to the polls on Election Day. In a prepared speech for the Martin and Coretta King Unity Breakfast on Sunday, Mr. Biden will argue that such actions are still necessary despite the progress of the last half-century.

“The legacy of the march in Selma is that while nothing can stop a free people from exercising their most sacred power as citizens, there are those who will do everything they can to take that power away,” Mr. Biden will say, according to the prepared remarks.

“Every eligible voter should be able to vote and have it counted,” he plans to say. “If you have the best ideas, you have nothing to hide. Let more people vote.”

The president’s actions come in the wake of his predecessor’s monthslong assault on the voting process during the 2020 election and the Jan. 6 riot that erupted at the U.S. Capitol after that predecessor, Donald J. Trump, repeatedly sought to overturn the election results.

The executive order is relatively limited in scope. It calls upon officials at federal agencies to study and potentially expand access to voter registration materials, especially for those with disabilities, incarcerated people and other historically underserved groups.

It also orders a modernization of the federally run Vote.gov website to ensure that it provides the most up-to-date information about voting and elections.

But the order does not directly address efforts by many Republican-led state legislatures to restrict voting, including measures that would roll back the mail voting that was established in many states during the pandemic.

Mr. Biden has said that he supports H.R. 1, a far-reaching voter rights bill that passed the House last week. It would weaken restrictive state voter identification laws, require automatic voter registration, expand mail-in voting and early voting, make it more difficult to eliminate voters from the rolls and restore voting rights to former felons.

That legislation faces a difficult challenge in the evenly divided Senate, where Republican opposition appears to make it highly unlikely that it can win the support of the 60 senators required to send it to Mr. Biden’s desk.

In the meantime, a senior administration official said Mr. Biden’s executive order was meant to show that the president was doing what he could.