Prince Harry and Meghan, Duchess of Sussex, will officially step down from royal duties on March 31.
Buckingham Palace has announced the exit will also see the couple close their Buckingham Palace office.
They will be represented through their UK foundation team from April 1 onwards.
The new guidance states Harry and Meghan will continue working with their existing patronages and are working to build a new non-profit organisation.
The couple will also retain their HRH titles, but will not actively use them.
Harry will keep his military ranks of Major, Lieutenant Commander, and Squadron Leader but will not use them during the 12-month trial period.
The couple announced their decision to step down from the royal family in an Instagram post last month.