The female cat may purr because she is in a good mood, relaxed, comfortable, or likes you. This is normal and there is no need to worry about it. However, if the cat often purrs for no reason, then there may be something wrong with it. It may be that the cat is sick and feeling uncomfortable, and needs to take the cat to the pet hospital for a check-up.
Tips:
You can pet the cat more often, so that the cat will be more satisfied and can also increase the distance between you and the cat. Feelings.