At one point during the festivities, onlookers who came to pay tribute sang "Happy Birthday" to the Queen as she greeted everyone before departing in her vehicle.
Last year, Meier told PEOPLE that a curtsy should be subtle and that the deeper and longer you pause shows more respect and formality.
Elizabeth was born on April 21, 1926, in Bruton Street, central London and became queen in 1952 at the age of 25, meaning she has now reigned for more than 67 years.
"Happy Birthday Your Majesty, Ma'am, Granny".
Members of the royal family joined Queen Elizabeth for Easter service at St. George's Chapel in Windsor Castle on Sunday, and it also happened to be her 93rd birthday.
At Buckingham Palace, the Band of the Irish Guards will perform a rendition of Happy Birthday in her honour on the forecourt as part of the Changing of the Guard ceremony.
She also celebrated her birthday more than a month later in June at the Trooping the Colour parade, an event which has marked the official birthday of the British Sovereign for over 260 years.
Gun salutes that are traditionally fired in London to mark the Queen's birthday have been delayed until Monday as they are never to be performed on Sundays.
Elizabeth II was born in London as the first child of the Duke and Duchess of York, later King George VI and Queen Elizabeth.
Prince Harry, Duke of Sussex, Catherine, Duchess of Cambridge, and William, Duke of Cambridge stepped out in their Sunday best, with Kate Middleton sporting a pastel periwinkle Alexander McQueen coat dress with a matching hat.
The Queen traditionally spends a month-long residence at Windsor Castle, known as Easter Court, each year.
Three cheers for The Queen soon followed, with the 93-year-old monarch recognising the crowd with a wave.
