Starbucks will require people visiting its coffee shops to buy something in order to stay or to use its bathrooms, the company announced in a letter sent to store managers on Monday.

The new policy, outlined in a Code of Conduct, will be enacted later this month and applies to the company’s cafes, patios and bathrooms.

“Implementing a Coffeehouse Code of Conduct is something most retailers already have and is a practical step that helps us prioritize our paying customers who want to sit and enjoy our cafes or need to use the restroom during their visit,” Jaci Anderson, a Starbucks spokeswoman, said in an emailed statement.

Ms. Anderson said that by outlining expectations for customers the company “can create a better environment for everyone.”

The Code of Conduct will be displayed in every store and prohibit behaviors including discrimination, harassment, smoking and panhandling.

People who violate the rules will be asked to leave the store, and employees may call law enforcement, the policy says.

Before implementation of the new policy begins on Jan. 27, store managers will be given 40 hours to prepare stores and workers, according to the company. There will also be training sessions for staff.

This training time will be used to prepare for other new practices, too, including asking customers if they want their drink to stay or to go and offering unlimited free refills of hot or iced coffee to customers who order a drink to stay.

The changes are part of an attempt by the company to prioritize customers and make the stores more inviting, Sara Trilling, the president of Starbucks North America, said in a letter to store managers.

“We know from customers that access to comfortable seating and a clean, safe environment is critical to the Starbucks experience they love,” she wrote. “We’ve also heard from you, our partners, that there is a need to reset expectations for how our spaces should be used, and who uses them.”

The changes come as the company responds to declining sales, falling stock prices and grumbling from activist investors. In August, the company appointed a new chief executive, Brian Niccol.

Mr. Niccol outlined changes the company needed to make in a video in October. “We will simplify our overly complex menu, fix our pricing architecture and ensure that every customer feels Starbucks is worth it every single time they visit,” he said.

The new purchase requirement reverses a policy Starbucks instituted in 2018 that said people could use its cafes and bathrooms even if they had not bought something.

The earlier policy was introduced a month after two Black men were arrested in a Philadelphia Starbucks while waiting to meet another man for a business meeting.

Officials said that the men had asked to use the bathroom, but that an employee had refused the request because they had not purchased anything. An employee then called the police, and part of the ensuing encounter was recorded on video and viewed by millions of people online, prompting boycotts and protests.

In 2022, Howard Schultz, the Starbucks chief executive at the time, said that the company was reconsidering the open-bathroom policy.

Manimatana Lee spent the past five years building one of the hottest commodities on the internet: a group of people who reliably watch her videos on TikTok.

She built an audience of nearly 10,000 followers with videos of herself vacuuming her house in Wisconsin while her youngest daughter napped in a carrier on her back. A video of Ms. Lee dancing and doing the dishes — while wearing her sleeping baby — has been watched more than one million times since November.

Now, with the Supreme Court soon to rule in a case that could determine whether TikTok could be banned in the United States over national security concerns, Ms. Lee and other Americans looking for alternatives are downloading Xiaohongshu, a social media app that is popular in China and little known outside the country.

“How funny would it be if they ban TikTok and we all just move over to this Chinese app,” Ms. Lee wrote on Monday on TikTok encouraging her followers to join her.

Xiaohongshu was the most downloaded free app in the U.S. Apple store on Tuesday. Over 300 million people, mostly in China, use the app, where they share short videos as well as still, text-based posts. People flocking to it said, in interviews and on the app, that they wanted to show they do not share Washington’s concerns about TikTok’s ties to China.

TikTok, which is available in more than 150 countries but not China, is owned by the Chinese internet company ByteDance. American creators who post videos on TikTok say the app has been a source of connection, entertainment and information since it became a sensation during the Covid-19 pandemic. Its secret sauce is its proprietary algorithm, technology that recommends a constant stream of short videos targeted to keep people scrolling.

But lawmakers in the United States and other countries have warned that the Chinese government could use TikTok to access data about its users such as location and browsing histories. Officials in Washington say they are also concerned that China could use TikTok to spread false information among the 170 million people who use it in the United States.

Xiaohongshu means “little red book” in Mandarin. Americans new to the app said they were not put off by the reference to a book of Mao Zedong’s sayings. Many call the app “Red Note.”

“I don’t really care if I’m using a Chinese app at all,” said Ms. Lee. “It’s like a place for me to escape reality. And if it’s making me feel good, I’m here for it.”

A group of American creators have sued the government over the law that could see the TikTok app forcibly sold or banned in the United States, and TikTok is paying their legal fees. Ms. Lee and another creator said in interviews that their interest in Xiaohongshu had not been incentivized by either company. TikTok did not respond to a request for comment.

The Americans on Xiaohongshu have rallied under the hashtag “TikTokrefugee,” which had been viewed 100 million times and sparked around 2.5 million discussion threads on the app by Tuesday.

Joining the app has put American users in closer contact with people online in China than they have ever been on TikTok. In China, people use Douyin, a very similar app that ByteDance used to develop the technology that made TikTok a worldwide hit. Douyin is difficult to access outside China.

Many shared tips on how to navigate the app, which is mainly made for and used by people who read and speak Mandarin. Some took screenshots and asked ChatGPT to translate posts, they said.

Xiaohongshu displays the city or province of Chinese users who post and comment, and the country for users outside China. “We are coming to the Chinese spies and begging them to let us stay here,” said one American user. “Approved, welcome to Red Note,” someone in Shanghai replied.

Until late December, 85 percent of Xiaohongshu traffic was from China, according to Similarweb, a data provider and website traffic tracker. The app is especially popular among women in their 20s and 30s, and its long comment threads have become a popular source of information for people to swap questions about everyday concerns, similar to Reddit.

Xiaohongshu did not respond to requests for comment.

On Tuesday, more than 100,000 people had joined a live group chat hosted by a user named “TikTok Refugee Club,” where people from around the world chatted with Chinese users about urban safety. In another group chat, which had been viewed more than 30,000 times, participants discussed censorship and shared tips in the comments on how to avoid being banned from the platform for bringing up politically sensitive topics.

Under another video posted by someone who said they were usually on TikTok, a user in China responded with a meme of a cat with paws outstretched. “I’m your Chinese spy,” the comment said, “give me all your data.”