While you’re hidden from a creature, that creature knows the space you’re in but can’t tell precisely where you are. You typically become hidden by using Stealth to Hide. When Seeking a creature using only imprecise senses, it remains hidden, rather than observed. A creature you’re hidden from is flat-footed to you, and it must succeed at a DC 11 flat check when targeting you with an attack, spell, or other effect or it fails affect you. Area effects aren’t subject to this flat check.
A creature might be able to use the Seek action to try to observe you.