Hillary Rodham Clinton addresses a conference of camp professionals in Atlantic City, N.J., in March. (Mel Evans/AP)

Hillary Rodham Clinton’s long-anticipated entry into the 2016 presidential race took shape Friday, with Democrats saying she will announce her candidacy on Sunday and begin a series of deliberately small discussions with voters next week.

The low-key rollout — no big rallies or lengthy speeches — will end months of speculation surrounding the overwhelming favorite for the Democratic nomination. Clinton intends to begin her second White House bid via social media, probably Twitter, and include a video that introduces her economic-centered campaign message before jetting to Iowa next week for public appearances, according to three Democrats with knowledge of her plans.

Behind the scenes, meanwhile, Clinton’s fundraising machine is coming to life. Her top bundlers are plotting aggressive outreach to thousands of Democratic donors over the weekend and into next week to urge them to send checks and make donations online as soon as the Clinton campaign’s Web site goes live.

The strategists and allies spoke on condition of anonymity because they were not authorized to discuss details of the forthcoming announcement. Spokesmen for Clinton’s now-robust campaign-in-waiting declined to comment Friday.

Former U.S. senator and secretary of state Hillary Clinton is expected to announce that she’s running for president in 2016. Here's the Democrat’s take on women’s rights, Benghazi and more, in her own words. (Julie Percha/The Washington Post)

Clinton’s go-slow, go-small start is the opposite of how many Republicans have entered or plan to enter the race. Instead of a splashy launch event, Clinton’s plan is a calculated understatement. She is scheduling a series of small roundtables and other give-and-take sessions with voters, first in Iowa and later in New Hampshire, South Carolina and Nevada — the states holding the first presidential primaries and caucuses early next year.

The idea is to showcase Clinton’s abilities as a problem-solver and crusader for the rights of those struggling to climb into or stay in the middle class. The intimate events with voters are also designed to help the former secretary of state connect with ordinary Americans and listen to their concerns, supporters said.

Jay Jacobs, a former New York Democratic Party chairman and longtime Clinton friend, said he thinks the events will present Clinton “as she is known by people who are close to her: as a very warm, genuine, thoughtful, certainly intelligent, regular person.”

“There’s been so much that we’ve seen that seems to create an image, by the press and by others, those who are looking to derail her, but now the voters are going to hear from Hillary,” Jacobs said.

Clinton’s human-scale approach is modeled on the listening tour she conducted across New York state at the start of her successful 2000 Senate race. She came to that campaign as a sitting first lady and political celebrity with no roots in New York, but her efforts to seek out New Yorkers’ opinions — in diners as well as people’s living rooms and kitchens — surprised many voters and some critics.

“It became a two-way conversation that impressed voters not by just what she said, but by how intently she listened,” Jacobs said. “I think that’s Hillary. That’s something that has worked before and it’ll work again.”

David Axelrod, who helped lead the insurgent 2008 Barack Obama campaign that eclipsed Hillary Clinton’s first presidential run, welcomed the new approach.

“Humility is the order of the day,” Axelrod said. “Last time, they launched as a big juggernaut cloaked in the veil of inevitability and at 20,000 feet. There was a tremendous backlash to that. It is imperative for her to go out, to meet people where they live, to make her case, to deliver a message, to listen to what they have to say and to ask for their votes.”

Axelrod added that Clinton must also articulate a message about economic mobility during her launch that’s “compelling and authentic,” rooted in her personal biography. “She needs to project what the cause is that she’s fighting for here and give people a sense of where they fit into that vision,” he said.

One open question for Clinton allies is what role her husband, former president Bill Clinton, and their daughter, Chelsea, will play in the campaign. Both have made splashy media appearances in the past week, with Chelsea on the cover of Elle and Bill on the cover of Town & Country. The former president told the magazine that he plans to be merely a “backstage adviser” to his wife, at least in the early stages of the campaign.

Widely considered by Democrats to be Obama’s heir apparent, Clinton has hired several of the president’s top campaign strategists to work on her 2016 bid.

In polls, Clinton is the dominant Democratic candidate, and in general election matchups she is at least slightly ahead of all likely Republican challengers.

The potential to become America’s first female president is a lodestar for Clinton’s campaign, and the soon-to-be candidate has strongly suggested that she will stress her path-breaking role.

Clinton resisted pressure from some Democrats to begin her campaign earlier this year, using the past several months to hone her message and assemble an extensive operation to run a campaign and raise money. She has recruited dozens of staffers who have been volunteering their time before the launch; her team signed a lease last week on office space in Brooklyn to serve as her national campaign headquarters.

Clinton’s Sunday announcement would come one day before the expected campaign launch of Sen. Marco Rubio (R-Florida), who is planning a major speech to supporters Monday afternoon at Miami’s Freedom Tower. On Friday, Rubio released a YouTube video, called “A New American Century,” previewing his announcement.

With Clinton’s launch, Republicans are revving up their attack machine. The Republican National Committee announced an online ad Friday to highlight past scandals, including her use of private e-mail at the State Department.

“From the East Wing to the State Department, Hillary Clinton has left a trail of secrecy, scandal and failed liberal policies that no image consultant can erase,” RNC Chairman Reince Priebus said in a statement. “Voters want to elect someone they can trust and Hillary’s record proves that she cannot be trusted. We must ‘Stop Hillary.’ ”

Like the small-scale rollout in Iowa living rooms, Clinton and her advisers are also modulating their fundraising early on to avoid appearing presumptuous and keep the campaign focused on a grass-roots effort. Clinton allies have been tamping down expectations for a massive influx of campaign cash, but her fundraisers anticipate a rush of major donors trying to get checks in the door on Day One.

“All the horses are in the gate just waiting for those gates to open,” said John Morgan, a Clinton fundraiser in Florida. “There’s really nothing to do until the gate opens. But the gate could open Sunday and it could be the flood gate. The only issue they’ll have is how fast can they raise the money, because the money is pent up.”

Clinton will raise only primary-season money at first, with a cap of $2,700 a donor. That is partly to avoid the appearance that Clinton is taking the nomination for granted. The focus on Internet appeals will free up Clinton to spend time on the trail talking to voters, rather than wooing wealthy donors at glitzy, high-priced fundraisers.

“I don’t think the first thing out of the gate she should be doing is a bunch of big fundraising events,” said one senior party strategist who requested anonymity to speak candidly.

The approach is a notable contrast to former Florida governor Jeb Bush, who has spent the better part of four months crisscrossing the country holding closed-door finance events for his Right to Rise political action committee and super PAC with tickets costing as much as $100,000 each.

“I think she’ll be in Iowa eating corn on the cob instead of clinking champagne flutes with donors,” Morgan said. “She can do this much quicker, much more efficiently because she’s not fighting for donors. Rubio, Bush, that whole crowd is in mortal combat for dollars. She’s not. That’s her advantage.”

The campaign is not expected to give titles to top bundlers or announce a list of finance committee chairs or members at the outset, according to Democrats with knowledge of the Clinton strategy.

One priority is creating an extensive small-donor network similar to the Obama campaign’s much-admired list from his 2008 and 2012 campaigns, and Clinton advisers see her announcement period as a ripe opportunity.

“We’re not going to take it slow,” said one Clinton fundraiser who spoke on the condition of anonymity to discuss the campaign’s internal plans. “The announcement is a good time to raise money, and we’ll have everyone out there asking people to support her candidacy.”

The campaign will be able to build on the efforts of Ready for Hillary, an outside group started in 2013 to lay the groundwork for Clinton’s run that has held more than 1,000 grass-roots events in all 50 states. The group amassed a donor pool of more than 135,000 people, the vast majority of whom gave contributions of $100 or less, according to PAC officials.

Ready for Hillary will not be able to coordinate with Clinton once she announces, but it could share its list of supporters with her campaign through a list swap, campaign finance lawyers said.

The group may not even have to take that step, however. Once Clinton declares her candidacy, the super PAC can simply direct its supporters to her Web site, allowing her campaign to quickly build a small donor list.

Once she’s officially in, Ready for Hillary plans to post online the names of hundreds of donors who have given or raised more than $5,000, according to a person familiar with the plans. That list — which includes at least 222 donors who gave $25,000 — would be valuable not just for Clinton’s campaign but for Priorities USA, the high-dollar super PAC planning to finance a pro-Clinton television advertising campaign and facing pressure to kick-start its fundraising.

Ahead of the campaign launch, Clinton released a new epilogue Friday for “Hard Choices,” her State Department memoir coming out this month in paperback. In it, she ruminates about a “memory quilt” she received as a gift after her granddaughter Charlotte’s birth last September.

“I wondered for a moment what a quilt of my own life would look like,” Clinton wrote. “There was so much more to do. So many more panels waiting to be filled in. I folded up the quilt and got back to work.”

Matea Gold and Dan Balz contributed to this report.