The prince and the US actress “want their wedding day to be shaped so as to allow members of the public to feel part of the celebrations too”, a spokesman said.
The group will be invited to watch the arrivals of the bride, groom and their guests at St George’s Chapel in Windsor Castle, a residence of Queen Elizabeth II’s located west of London.
They will also be able to watch the royal couple depart in a horse-drawn carriage.
Those invited include 1,200 members of the public from across Britain, chosen to represent a broad range of backgrounds and ages, including young people who have “shown strong leadership” and served their communities.
There will also be 200 people from charities and organisations associated with the couple, 100 pupils from local schools, 610 members of the castle community and 530 royal and crown staff.
Harry and Meghan had already announced they would make a short carriage ride through the town of Windsor after their wedding on May 19, to “share their celebrations with the public”.
There will be a reception afterwards at St George’s Hall in Windsor Castle, while Harry’s father Prince Charles, the heir to the throne, will host a private party in the evening.