Are you asking from a technical or design point of view?
Because giving technical advice is rather hard without a definition of what good hiding is.
From the top of my head the easiest thing would be to just set possible hide locations and make the AI pick one at random.
However that also makes it quite easy to find it especially when playing the game multiple times.
If you have multiple “hiding” characters. A cool behavior would be roaming around. Which at least used to be something we did a lot back in the day. Actively avoid the seeker by keeping track of where he / she is and moving away from that location / staying on observation distance. Which creates a struggle between keeping the seeker in sight while also staying far enough away that you can not be seen yourself. And might encourage the seekers to be more stealthy themselves.
Which is a rather difficult thing to implement though.