This is what we found on Wikipedia regarding the Palace of Holyroodhouse Entry Tickets:

Queen Elizabeth II, Queen of the United Kingdom and the other Commonwealth realms, died on 8 September 2022 at Balmoral Castle in Scotland, at the age of 96. Elizabeth's reign of 70 years and 214 days is the longest of any British monarch. She was immediately succeeded by her eldest child, Charles III, who was declared king from prince of the United Kingdom.

Elizabeth's death set in motion the final version of Operation London Bridge, a funeral plan first devised in the 1960s, and Operation Unicorn, the plan for the Queen's death in Scotland. Elizabeth's coffin lay at rest in St Giles' Cathedral in Edinburgh from 12 to 13 September, after which it was flown to London, where it lay in state in Westminster Hall from 14 to 19 September. An estimated 33,000 people filed past the Queen's coffin in Edinburgh, and approximately 250,000 people queued to pay their respects in London. The United Kingdom observed a national mourning period of 10 days.

Elizabeth's state funeral on 19 September was the first held in Britain since Winston Churchill's in 1965. A funeral service was held at Westminster Abbey, followed by a procession to Wellington Arch which featured around 3,000 military personnel and was watched by approximately one million people in central London. The state hearse then transported the Queen's coffin to Windsor, followed by another procession through Windsor Great Park and a committal service at St George's Chapel at Windsor Castle. The Queen was interred later that evening with her husband, Prince Philip, in the King George VI Memorial Chapel, in a private service attended only by her closest family.

Designated as a public holiday in the UK and several Commonwealth countries, the state funeral included dignitaries from around the world and featured the largest security operation ever mounted in the UK. Coverage of the state funeral was one of the UK's most watched special television broadcasts, surpassing the wedding of Prince William and Catherine Middleton, the previous most-watched royal event of the 21st century. The period of official mourning and the funeral was estimated to have cost the government £162 million.