There is no hard rule about age, but the puppy must be old enough to understand the relationship between their behavior and the correction. That age may differ for different dogs.
However, you can usually see when you notice that your puppy avoids certain items or situations with which he has had a negative experience. When you decide to purchase a collar, make sure it is designed for puppies or small dogs.
These models usually have lower settings and more control over the settings so that the dog does not receive unnecessary or traumatic correction.