Warren Buffett talks to his kids about his will. You should too.

The legendary stock picker, 94, shared his strategy this past week for how to pass wealth on to the next generation while minimizing family conflicts. His advice is applicable, he says, even if you aren’t a billionaire like he is.

In comments released Monday to shareholders of his company, Berkshire Hathaway, Buffett offered a simple but often overlooked estate-planning suggestion for parents: “When your children are mature, have them read your will before you sign it," he wrote. “Be sure each child understands both the logic for your decisions and the responsibilities they will encounter upon your death."

“You don’t want your children asking ‘Why?’ in respect to testamentary decisions when you are no longer able to respond," Buffett wrote in the letter, which also announced a gift of about $1.15 billion of his Berkshire shares to four family foundations.

Buffett, who has been donating big chunks of his fortune to those foundations and other charities for years, is currently worth about $150 billion.

Discussing the contents of your will is a tactic that is heartily endorsed by estate planners and financial advisers. Buffett’s letter, said Sean Maher, an estate planner in Audubon, Penn., is a “call to action to be very transparent and not have surprises in your will."

Sharing and discussing the contents of a will can be emotionally difficult for parents and adult children. Many feel uncomfortable talking about money and death. And parents often fear disclosure could create conflict among their children.

But if you keep your wishes under wraps until you’re gone, those conflicts are likely to surface anyway, estate planners say. When parents are transparent about their wishes, they can often help their children manage any conflicts and reach an understanding, if not forge closer ties and greater respect for one another, said Maher, co-author of “The Greatest Gift: 9 Principles for the Transfer of Your Legacy Along with Your Wealth."

A no-surprises policy also avoids creating upset at a time when beneficiaries are grieving and prone to strong emotions, estate specialists say. It allows adult children to ask a parent to clarify their intent.

Especially in extreme situations, such as when a child is written out of a will, disclosing the terms yourself “is the greatest gift you can give your heirs," who might otherwise become the target of a disappointed sibling’s anger, said Maher.

It is a conversation many American families aren’t having. According to a survey of 2,200 individuals last year, 35% said they have no plans to discuss the transfer of wealth from one generation of their family to another. Nearly 40% said they hope to do so eventually. Only about one-quarter have had such a discussion, according to the survey from financial advisory firm Edward Jones, consultant Next360 Partners and research firm Morning Consult.

Ideally, families should have more than one conversation, said Joseph Coughlin, director of the Massachusetts Institute of Technology AgeLab and senior adviser to Next360 Partners.

“Emotion is going to guide and frame the conversation and decisions about the division of wealth," he said. “The only way to keep people from being stressed, surprised, and angered is to have those conversations in small bits over time."

With many families living far apart, “you have to make a real effort," he added.

When Nicole Luna asked her father, Clifford Glade, if he would invest some of her money earlier this year, he used it as an opportunity to start talking about her inheritance. In bits and pieces, the 73-year-old veterinarian, who lives in the Florida Keys, filled her in on the details of his real estate and investments. He discussed his veterinary practice and another small healthcare company he owns. He introduced her to his accountant.

Luna described it as a series of minor conversations. “The last time I came to visit, he told me the combination to the safe," she said. Luna is an editor and doesn’t want to run his companies, so they are discussing what to do with them.

He said he hopes the conversations convey something deeper: “I want you to understand that you’re financially free, but at the same time you need to have a purpose."

Many wealthy families seek over time to build a culture that facilitates communication about goals for their money.

Buffett in his letter said that since the death of his first wife, Susan Thompson Buffett, his three children’s philanthropic activities have dramatically increased, giving him a chance to observe them managing teams of workers. That has made him comfortable giving them full responsibility for distributing all of his Berkshire holdings, which comprise 99.5% of his wealth, he said.

“They have different views in many cases from both me and their siblings but have common values that are unwavering," including helping others and not being preoccupied by wealth, he wrote in his letter.

Not sharing your will with your adult children can leave them unprepared to handle a windfall.

When Ebonee Moore’s father died in 2017, she didn’t know there was money left behind for her until her aunt discovered a stack of financial documents. “He lived so modestly, I never thought to ask about a will or inheritance," said Moore, 41.

Moore’s father had multiple life-insurance policies, retirement accounts, and annuities for Moore and her two sisters. The roughly $200,000 inheritance allowed Moore to put $6,000 down on her first home, giving her seven children room to spread out.

But she believes understanding her inheritance earlier would have given her a chance to learn more about investing and financial planning. She used some of the money to pay off student loans that weren’t accruing interest, which she now regrets.

Coughlin said the best time to have a discussion is when the family can get together without stress.

Maher recommends giving adult children a summary of your will before a family meeting. Wills can be complicated, so ask your lawyer or estate planner to attend the meeting to explain the details and answer questions.

Follow-up with children individually, especially those who are quiet in the group session.

Buffett said he has received questions or commentary from all three of his children, now in their 60s and 70s, and has often adopted their suggestions in revisions to his will.

“There is nothing wrong with my having to defend my thoughts," he wrote. (He declined to comment for this article. His children, Susie, Howard and Peter Buffett, didn’t respond to requests for comment.)

Buffett said he revises his will every “couple of years, often only in very minor ways."

That underscores that these conversations aren’t “one and done," said Coughlin, who notes that families change over time, with births, deaths, divorces and marriages.

Lauren Gadkowski Lindsay, an adviser in Houston, recommends following Buffett’s example by writing a letter to your beneficiaries that outlines your values in plain English. She also said to write down who you wish to inherit your possessions, which can have sentimental, if not monetary, value.

Lindsay said her mother has done so with her antiques, sharing stories that make it clear why she chose the recipient.

Maher says the only thing he disagrees with Buffett about is the advice to postpone signing your will until your adult children have read it. While that is a nice way to signal an openness to making changes, those who delay signing risk dying without the document in place. In a worst-case scenario, that might leave assets to be divided according to state rules. He said it makes more sense to sign the will and then revise it later if you want to make changes after consulting with family.

—Ben Eisen contributed to this article

Write to Anne Tergesen at anne.tergesen@wsj.com and Dalvin Brown at dalvin.brown@wsj.com