WASHINGTON — One of President Obama’s top priorities during his last months in office is to help make sure that Hillary Clinton succeeds him. To do so, the president will make at least a dozen campaign appearances in battleground states from now to Election Day on Nov. 8.

Mr. Obama’s task is not to try to persuade independents or Republicans that they should choose Mrs. Clinton over Donald J. Trump, the Republican nominee, according to White House officials and the Clinton campaign. Instead, he will urge his most enthusiastic supporters — young voters and African-Americans — to register or to be sure to turn out to vote for Mrs. Clinton.

“The president’s focus is on getting the Obama coalition to the polls,” said Jen Psaki, the White House communications director.

Most of his appearances will be timed to coincide with voter registration deadlines and the start of early voting, White House officials said. On Sept. 13, for example, Mr. Obama will appear at a rally in Philadelphia, four weeks before the last day that Pennsylvanians can register to vote.