Why do cats purr?

Cats purr because they feel comfortable, relaxed, and happy. Cats generally purr easily when they eat, breastfeed, or are petted by their owners. Don’t worry, this is a purring sound. This is normal; but cats will also purr when they feel uncomfortable, which can relieve discomfort.
Tip:
When the cat purrs, you can stroke the cat more, so that the cat will be more satisfied.