What's the meaning of 'ER' and what will be the symbol of King

The cypher is the personal seal of the British monarch and like a host of other things will need to be updated for the new king.

Chemical symbol - Wikipedia

7 Chakra Chart - 56 Zip Pouch by Serena King - Fine Art America

What does ER stand for and will it be replaced with CR?

King of the Greek Gods: Who is Zeus?

What will ER change to now Charles is King? Royal Cypher meaning ahead of CIIIR change

What did ER stand for in the Queen's signature?

On throne during Charles III's - The Voice of Sikkim

Harald Hardrada - Wikipedia

What will ER change to when Charles is king?

Will Prince Charles replace the Queen on money and stamps in the U.K.? What will change after her death