There are a few ways to find a haunted house in The Sims 4:

• The Gallery: The Gallery is a collection of user-created content that is available for download. There are many haunted houses available in the Gallery, so you can find one that fits your needs.
• The Build/Buy Mode: You can also create your own haunted house in Build/Buy Mode. There are a variety of haunted house-themed objects available, so you can create the perfect haunted house for your Sims.
• The World Adventures Expansion Pack: The World Adventures Expansion Pack includes a haunted house called the Graveyard. The Graveyard is located in the Magnolia Promenade world, and it is a great place to find ghosts and other supernatural creatures.
• The Paranormal Stuff Pack: The Paranormal Stuff Pack adds a new lot type called Haunted House Residential. This lot type is perfect for creating your own haunted house, and it comes with a variety of haunted house-themed objects.

Once you have found a haunted house, you can start exploring it with your Sims. Be careful, though, as haunted houses can be dangerous!