Full guidance on wearing face coverings in shops in England has been released, less than 12 hours before the new rules come into force.
Coverings will be mandatory in enclosed public spaces including supermarkets, indoor shopping centres, transport hubs, banks and post offices.
They must also be worn when buying takeaway food and drink, although they can be removed in a seating area.
Those who break the rules could face a fine of up to £100.
There are exemptions for children under 11, those with disabilities or certain health conditions, such as respiratory or cognitive impairments that make it difficult for them to wear a face covering.
The government has been accused of mixed messaging over takeaways, with trade bodies and MPs saying there had been confusion about how the rules would apply.
A Department of Health spokesman said: "If you are in a premises where you are able to sit down and consume food or drink that you have bought, then you can remove your face covering in order to eat and drink on site."
Speaking before the guidance was published, Kate Nicholls, chief executive of UK Hospitality, said the messaging from the government had been contradictory and it was "very late in the day" for the guidance to be confirmed.
"It's really unhelpful to have that confusion because the single biggest thing we need now is to rebuild consumer confidence and that needs clear, unambiguous messaging," she told BBC Breakfast on Thursday.
The criticism came after ministers and Boris Johnson's official spokesman contradicted each other over how the rules would apply to takeaways and sandwich shops.
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Wearing a face covering will not be made mandatory in other venues that have measures in place to protect staff and the public from Covid-19 including:
Eat-in restaurants and pubs Hairdressers and other treatment salons Gyms and leisure centres Cinemas, concert halls and theatresFace coverings have been compulsory in shops in Scotland since 10 July. Shoppers are not currently required to wear them in Wales or Northern Ireland, although this is being considered.
Mr Hancock announced on 14 July that wearing a face covering in shops and supermarkets would be compulsory from Friday, 24 July, with anyone failing to comply facing a fine of up to £100.
Can police make me cover my face?
The Police Federation, which represents front-line officers, says they can't spend their time patrolling thousands upon thousands of outlets.
Shop staff and security guards can already detain shoplifters while waiting for the police to arrive. However, the general power of the citizen's arrest is only exercisable to apprehend criminals committing offences that would go before a judge and jury. A penalty ticket for being socially obnoxious would not cross that high bar.
Police leaders hope shop managers will refuse non-mask wearers entry - rather than turning to the police to solve the problem.
Met Commissioner Dame Cressida Dick has said that police in London would only enforce the wearing of coverings in shops "as a last resort" - if people not wearing a covering refused to leave a shop or became "aggressive".
Tracy Cannard, who works in a supermarket and is a representative of the shopworkers' union USDAW, said while increasing numbers of customers were choosing to wear masks this still only amounted to around 20% and making it compulsory would help her feel safer.
James Lowman, chief executive of the Association of Convenience Stores, said the body was advising its members to communicate advice on face coverings through posters and informal conversations rather than challenging customers who did not wear one.
He said incidents of verbal and physical abuse of shop workers had increased during lockdown and retailers did not want to risk creating a "flashpoint" for confrontation.
Face coverings are already compulsory on public transport in England and Scotland, as well as most buses, trains and ferries in Northern Ireland.
They will be mandatory on public transport in Wales from 27 July.
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