Becoming a US presidential candidate also made Kamala Harris' name go down in history as the first woman of color nominated by a major party to run for the White House, according to Reuters.

Democratic delegates began voting online this week. To win the nomination, a candidate must have more than 2,350 delegates.

Ms Harris became the Democratic front-runner after President Joe Biden ended his re-election campaign last month under pressure from the party amid concerns about his health and age.

The US vice president quickly won the support of party heavyweights and was the only candidate qualified for the party's ballot.

"I'm thrilled to know that we have enough delegates to secure the nomination. And then later this month, we will gather in unity in Chicago, where we will have the opportunity to celebrate this historic moment together," Harris said. President Biden said he "could not be prouder" of his endorsement.

The Democratic National Committee has pledged to announce its presidential nomination by August 7, ahead of the party’s national convention in Chicago from August 19-22. The committee said the online vote was necessary to ensure the nomination process was completed by August 7, the date Ohio law requires a nominee to be nominated in order to proceed to the state’s ballot.

Vice President Kamala Harris plans to meet with top candidates for her running mate this weekend before making a decision, Reuters reported. Harris met with Transportation Secretary Pete Buttigieg, one of the potential candidates, for 90 minutes on August 2.

Harris is expected to make a decision by August 5 before making her first appearance with her running mate in Philadelphia the following day. Other potential names include Pennsylvania Gov. Josh Shapiro, Minnesota Gov. Tim Walz, Kentucky Gov. Andy Beshear, Illinois Gov. JB Pritzker and Sen. Mark Kelly.