While "payer" is often used in casual speech and writing, the official and more accurate spelling is "payor".
Here's why:
* Origin: The word "payor" comes from the verb "to pay" with the suffix "-or" indicating the one who performs the action.
* Dictionary definition: Dictionaries like Merriam-Webster and Oxford English Dictionary list "payor" as the primary spelling.
While both spellings might appear in various contexts, "payor" is the grammatically correct and preferred spelling.