As part of eight days of national mourning, people gathered at royal palaces to leave flowers.
While religious and political leaders expressed support for the 94-year-old queen, the world's oldest and longest-reigning monarch.
Her husband Prince Philip, who was officially known as the Duke of Edinburgh, died at Windsor Castle on Friday. He was 99.
At Canterbury Cathedral on Sunday (April 11), Justin Welby, leader of the global Anglican Communion, said the fact the prince had lived to within two months of his 100th birthday - did not soften the blow for those who had loved him.
“Loss is loss. For each person it is felt individually and reaches into the heart variously. We cannot ever know how others feel, nor do two people feel the same. It is simply lost. Some bear it apparently easily, for others it is crushing."
Buckingham Palace have said the funeral would be held on Saturday April 17.
Marked with long-established plans redrawn and scaled down because of COVID-19 restrictions.
There will be no public processions, and it will be held entirely within the grounds of Windsor Castle and limited to 30 mourners.
Prince Harry will return from the US but his wife Meghan, who is pregnant with their second child, will not, on her doctor's advice.
A topic of much discussion among mourners in Windsor.
"Harry should come back. Meghan, I think, okay, she's got her own issues with the monarchy, but you know Harry I think should be there for his grandfather.”
“I think Meghan should come with him to support him, try and show some unity. Part of me understands why she's not coming back, but I think that's a mistake.”
It will be Harry's first trip back to the UK since an explosive interview last month given by the couple to Oprah Winfrey.
Officials say they hope the occasion will help reunite the family and rebuild ties.