Parmesan hope this will help though I think its just for UK residents:
For many people, receiving a congratulatory card from The Queen to mark a significant birthday or wedding anniversary is a very special part of their celebrations.
Since 1917, the Sovereign has sent congratulatory messages to people celebrating notable birthdays and anniversaries. The Queen will send a congratulatory message on the following occasions.
Wedding anniversaries
The Queen sends messages for diamond (sixtieth), sixty-fifth and platinum (seventieth) wedding anniversaries and then every year thereafter.
Her Majesty does not send a message for Silver (twenty-fifth), Ruby (fortieth) or Golden (fiftieth) wedding anniversaries.
Birthdays
The Queen sends messages for one hundredth and one hundred and fifth birthdays and then every year thereafter.
The Queen's congratulatory messages consist of a card containing a personalised message with a facsimile signature. The card comes in a special envelope, which is delivered through the normal postal channels.
The delivery of these messages is arranged by the Anniversaries Office, part of the Private Secretary's Office in the Royal Household, based at Buckingham Palace.
The Pension Service informs the Anniversaries Office of birthdays for recipients of UK State pensions. But, for data privacy reasons, there is no automatic alert from Government records for wedding anniversaries.
For this reason, to make sure that a message is sent for birthdays and wedding anniversaries alike, an application should preferably be made by a relative or friend in advance of the special day. Requests for residents of Banffshire can be made by writing to the Lieutenancy Office.
In order to process these a copy of the Birth or Marriage Certificate will be required.