Presidents, prime ministers and monarchs from around the world will travel to London over the weekend to pay their respects to Queen Elizabeth.
They will attend a reception at Buckingham Palace to be hosted by King Charles the day before her funeral.
US President Joe Biden and French President Emmanuel Macron are among the most high-profile guests from overseas who have confirmed they will be attending.
Heads of state and other senior foreign dignitaries will be asked to gather at the Royal Hospital, a retirement and nursing home for veteran soldiers in west London, and are expected to travel in groups to Westminster Abbey, a senior Buckingham Palace official said.
The funeral will be one of the biggest policing events in Britain's history as world leaders, kings and queens and huge crowds from home and abroad descend upon London for the event.
King Charles and Camilla, the Queen Consort, will hold a reception at Buckingham Palace on Sunday, the official state event before the funeral.
Foreign dignitaries who do come to Britain will also be invited to visit the Queen's Lying in State inside parliament's Westminster Hall ahead of the funeral.
"Her Majesty's passing has left many people, across many continents, with a profound sense of loss," said the Earl Marshal, Edward Fitzalan-Howard, the Duke of Norfolk, England's most senior peer who is in charge of state occasions.
"It is our aim and belief that the state funeral and events of the next few days will unite people across the globe."
Immediately after the funeral on Monday, Britain's foreign minister James Cleverly will host a reception for guests at nearby Church House, as members of the royal family head to Windsor for the queen's burial.
While the dress code for the funeral is up to Buckingham Palace, British diplomats are advising foreign attendees to wear dark formal clothing, although national dress may also be worn. Serving military personnel will be able to wear ceremonial dress - with or without swords.
Invitations were sent out by Britain to heads of state of nearly every country in the world apart from Syria, Venezuela, Afghanistan, Russia, Belarus, and Myanmar.
Syria and Venezuela are not invited because Britain does not currently have diplomatic relations with those states. Afghanistan was not invited due to the current political situation, a source said.
Russia and Belarus are not being invited to send any representatives because of the invasion of Ukraine.
In total, foreign office officials have handwritten around 1,000 invitations for the funeral and the reception with King Charles on Sunday.
The deadline to accept funeral invitations passes on Thursday, after which officials will finalise the seating plan.
A group of British lawmakers sanctioned by China have criticised the decision to invite the Chinese government to the funeral.
They demanded that China's representatives are barred from the Palace of Westminster, where the queen's body is lying in state, after parliament voted last year to call the treatment of the mainly Muslim Uighur community in Xinjiang as genocide.
Chinese Vice President Wang Qishan is expected to represent China at Queen Elizabeth's funeral on Monday, a British foreign office source said on Thursday.
Britain's government will not provide a guest list of all the foreign leaders who will attend, partly for security reasons.
The transport arrangements are being finalised, as is the final seating plan, a government official said.
Members of the royal families of several European countries, including Belgium and the Netherlands, have said that they will travel to pay their respects.
Among the politicians who will also attend are European Commission President Ursula von der Leyen, New Zealand Prime Minister Jacinda Ardern and the President of India Droupadi Murmu.