Joseph R. Biden Jr. will announce a sweeping new $775 billion investment in caregiving programs on Tuesday, with a series of proposals covering care for small children, older adults and family members with disabilities. His campaign hopes the plan will land with particular resonance during a pandemic that has severely affected the caregiving needs of millions of American families.

The speech, near his home in Wilmington, Del., will be the third of four economic rollouts that Mr. Biden, the former vice president and presumptive Democratic nominee, is doing before the Democratic National Convention next month. He is seeking to blunt one of the few areas of advantage — the economy — that President Trump maintains even as Mr. Trump’s overall standing has dipped.

Mr. Biden’s plans are intended to appeal to voters who are now more acutely aware of how essential caregivers are, as a health crisis has shuttered schools — a source of child care for many Americans — and limited the options to care for older relatives who are more vulnerable to the coronavirus.

But they are also aimed at the caregivers themselves, promising more jobs and higher pay. His campaign estimated that the new spending would create three million new jobs in the next decade, and even more after accounting for people able to enter the work force instead of serving as unpaid, at-home caregivers.

In a conference call outlining the plan on Monday night, the Biden campaign framed the issues as an economic imperative to keep the country competitive globally, and to enable it to recover from the economic crisis brought on by the pandemic. The United States is the only rich country without paid family leave and has no universal child care; research has shown that labor force participation has stalled because of that.

But advisers to Mr. Biden, whose campaign has made empathy a central component of his 2020 candidacy, also repeatedly invoked the former vice president’s own history as a single father. Mr. Biden’s first wife and his 1-year-old daughter died in a car accident in 1972, shortly before he was first sworn into the United States Senate. His two sons survived the accident.

The Biden campaign is expected to announce proposals to eliminate the waiting list for home and community care under Medicaid, which has roughly 800,000 people on it; provide fresh funding to states and groups that explore alternatives to institutional care; and add 150,000 new community health workers. His campaign said that coronavirus outbreaks in nursing homes had highlighted the necessity of providing care for aging adults at home.

For young children, he is proposing to start with a bailout for child care centers, many of which are at risk of closing amid the pandemic because they are financed almost entirely by private payments. Even before lockdowns began, they operated on very small profit margins.

Mr. Biden will also propose national pre-K for all children ages 3 and 4, and his campaign pointed to research that has shown that such programs help women work and shrink racial and socioeconomic achievement gaps.

The plan would address the dearth of child care by providing financing for the construction of new child care facilities, including at workplaces and in rural areas.

Mr. Biden’s plan also calls for increased pay for child care workers — who are disproportionately women and minorities — along with health benefits, career training and the ability to unionize. A campaign document about the plan said: “There is no reason an educator teaching toddlers should be making less than a similarly qualified kindergarten educator.” On average, preschool teachers in the United States earn less than $30,000 a year, while kindergarten teachers earn over $50,000, according to researchers at the University of California, Berkeley.

The plan would provide benefits for people who don’t work to care for family members, an idea that has recently gained support from both parties. The proposal would give unpaid caregivers a $5,000 tax credit as well as Social Security credits.

Mr. Biden’s campaign said the programs, some of which would be operated with state and local officials, would be paid for by rolling back some taxes on real estate investors with incomes over $400,000, as well as by increasing tax enforcement on the wealthy.

Mr. Biden will speak in New Castle, Del., not far from the home where he has mostly stayed put since the coronavirus began sweeping the country in March. His first economic address was focused on reinvigorating manufacturing and strengthening “Buy American” rules; the second was on building the infrastructure of new, greener economy; and the final one will be about advancing “racial equity,” the campaign has said.