But it said if a customer is able to sit down and consume food or drink they have purchased, the face covering can be removed to eat or drink on site.
Face coverings will be mandatory for shops and supermarkets, banks, building societies and post offices.
They will not be required in places such as restaurants and pubs, hairdressers, gyms, leisure centres, cinemas, libraries, museums and theatres.
A Department of Health and Social Care spokesperson said: “From Friday 24 July, it will be mandatory to wear a face covering in shops and supermarkets, as is currently the case on public transport.
“If a shop or supermarket has a cafe or a seating area to eat and drink, you can remove your face covering in that area.”
People are now required to wear face masks in shops and supermarkets in England, but they will also need to cover their mouths and noses when entering sandwich shops or takeaways, according to the government’s guidance.
In an attempt to slow the spread of coronavirus, the Department of Health and Social Care confirmed face coverings will be required in shops and takeaways if people intend to take their food and coffee away.
The government has been accused of sowing confusing over whether face masks must be worn in sandwich shops and takeaways.
The health secretary, Matt Hancock, announced on 14 July that wearing a face covering in shops and supermarkets will be compulsory from 24 July.
However, the prime minister’s official spokesperson later said sandwich shops were exempt.
Mr Hancock said last week: “You do need to wear a face mask in Pret because Pret is a shop. If there’s table service, it is not necessary to have a mask. But in any shop, you do need a mask. So if you’re going up to the counter in Pret to buy takeaway, that is a shop.”
But the prime minister’s official spokesperson later said: “We will be publishing the full guidance shortly but my understanding is that it wouldn’t be mandatory if you went in, for example, to a sandwich shop in order to get a takeaway to wear a face covering.
“It is mandatory… we are talking about supermarkets and other shops rather than food shops.”
The new law states that it does not apply to “an area within or adjacent to a shop where seating or tables are made available by that business for the consumption of food and drink” by customers.
The change will be enforced using a new set of health protection regulations, which give police the power to fine people £100 for refusing to wear masks, and “use reasonable force” to remove them from shops.
The law, which was published on Thursday afternoon, states that “no person may, without reasonable excuse, enter or remain within a relevant place without wearing a face covering”.
It does not apply to children under the age of 11, staff, employees and people “providing services” for the business.
A “reasonable excuse” includes physical or mental illnesses, or disabilities, that prevent wearing a mask.
People who cannot put one on “without severe distress” are also exempt under the law, alongside people who go inside to “escape a risk for harm”.
The regulations state that masks do not have to be worn if “it is reasonably necessary to eat or drink”.
A face covering is legally defined as “covering of any type which covers a person’s nose and mouth”.
People have been advised to wash their hands before putting on a covering or mask or taking it off, and to avoid touching their eyes, nose, or mouth while wearing one.
Face coverings should be stored in a plastic bag until they can be washed or disposed of, the Department of Health and Social Care said.
Tom Ironside, director of business and regulation at the British Retail Consortium, said: “While enforcement of this policy will be handled by the police, the ultimate responsibility remains with customers who must ensure that they wear a face covering when going into stores.
“Our shopping experience is changing, and we ask customers to be respectful and considerate when the new rules come into force tomorrow.
“The regulations and more detailed guidance that the government has told us to expect is now overdue. Every passing hour limits the time that retailers have to implement the new guidance.”
A spokesperson for Sainsbury’s said: “The British Retail Consortium has explained that retail colleagues are not expected to enforce the new rules.
“The guidance we have shared with our colleagues reflects that.”
Earlier this month, national police leaders said forces were “unaware” of the impending announcement that face masks would be made mandatory in shops.
On Wednesday, Britain’s most senior police officer said she hoped shoppers who refuse to wear masks will be “shamed” into compliance.
Metropolitan Police Commissioner Dame Cressida Dick told LBC that calling the police over someone failing to wear a face covering should only be “a last resort”.
Meanwhile, the police and crime commissioners for Devon, Cornwall and Thames Valley have said officers will not attend incidents where shoppers refuse to wear masks, unless they turn violent.
In Scotland, face coverings are already mandatory in shops.
Passengers have been required to wear face coverings on public transport in England since last month.