The Queen of Great Britain “passed away” recently. To “pass away” means to die. Given that the event was recent the present perfect is used: the Queen “has passed away”. You could also say …” has died”.
There are other ways to say the same. The Queen of Great Britain
- “is at rest”
- has “left this world”
- “is no longer with us”
- “is departed” or “has departed”.
The Spanish King sent a message to the new King of Great Britain, King Charles the 3rd, and the text included: …” the news of the passing of her Majesty Queen Elizabeth 11…” (11 = 2nd). “Passing” (el paso) in this context is a noun, not a verb.
“Passing of” is the same as “passing away”, meaning to die. So the Queen “has passed away” or one can refer to the “passing of” the Queen. Do not use “has passed of”. That is wrong.
“Passing of” can also refer to an era or period of time. So, the majority of British people are mourning (de luto) the “passing of” the Queen, and the “passing of an era” (el paso de una era), that is, her long reign (reinado).