Choosing the right bedroom door lock will take a little consideration of your unique needs. An interior door can be designed to only lock from the inside to allow for privacy in the room. Here are some considerations when making your selection.
Generally, interior doors do not need keyed locks, so they probably have a thumb lock. These may be a push button lock or a simple turning lever in the center of the door.
Since interior door locks do not have keys, the exterior of the locks have either a slotted release that can be turned with a coin, or a small hole that can be unlocked by inserting a long, thin piece of metal that releases the door lock. The benefit of these releases is that if the door gets locked and closed, you can unlock it from the outside. The con is that it can reduce privacy and security.
For extra privacy, you can add a surface bolt to the interior of the room. These locks install on the door and slide to latch into a holder on the door frame. They aren’t on the doorknob, so they cannot be unlocked from the outside. For this reason, they are appropriate for an adult’s bedroom, not a child’s. They should be mounted at the top of the door to prevent access by small children.