Seek

The Seek action leaves it up to you how long a search should take. Use common sense. Most of the time, just trying to spot a creature hiding in a small area, or something else you could find with a simple Seek action rather than a longterm Search exploration activity, should default to a single action. The biggest distinction is whether something uses 3 actions or fewer—and can therefore be accomplished in a single turn—or requires significantly longer and can't be accomplished in an encounter at all. Consider whether it makes sense for the character to pull this off during the encounter or not, and whether that could be an interesting wrinkle in the story.