Wish someone "Happy Birthday," perhaps

SENDACARD

Think of a paper tradition that often arrives by mail to mark special occasions like anniversaries or holidays.

This clue plays on the idea of how you might celebrate someone’s birthday. Instead of literally saying "Happy Birthday," you could send a card—a common way to share the greeting. The answer combines the action ("send") with the object ("a card") into one word, "SENDACARD," making it a straightforward charade-style clue. It’s a hint at the physical act behind the well-wishing.