Dogs bark because it is one of their primary means of communication. They are social animals that have evolved to live in packs. But barking is only one means by which they communicate to one another not the only one. It is an extreme signal that expresses joy or fear. If a dog is barking incessantly then something is wrong. It is not natural for a dog to bark all the time.
A dog owner has to think like a dog to control incessant barking. You have to work out what your dog is trying to tell you. It may be your dog is barking because you have not heard his other signals. It is the equivalent of shouting to make yourself heard.
Perhaps your dog is lonely. A dog that is left alone all day will bark to attract attention. A dog needs its pack and for a domestic dog that is you. If you have to be out at work or school then consider finding a dog walker.
It is possible that a dog is not a suitable pet for you if you need to spend long periods out of the house. A cat or a lizard might be better for your needs. Dogs are intensely social. They get anxious when they alone.
If the dog barks incessantly when you are there it is asking for your attention. That may be for a good reason. It may want to go outside to attend to a call of nature. It may even be warning you about something. Dogs have woken their owners and saved them from burning houses. Your house may not be burning down but the dog may sense something in your behaviour that is not quite right. Helper dogs are trained to earn epilepsy suffers when an attack is imminent. They are highly sensitive to changes that you may not notice. A dog will often respond to depression in a family member. A dog can be like the canary in the mine it can detect psychological and social tensions in the household.
If there is no obvious reason for the dog to bark incessantly then it may be possible to train it not to bark so much. Training collars are often helpful in this respect as they are in other forms of behaviour. A collar that delivers a small electric shock when a dog barks may be enough to prevent excessive barking. There are also collars that deliver a burst of citronella when a dog barks. Either can be useful. Long haired dogs may not feel the sting of an electric shock and short haired or small dogs might find it too sharp. Be guided by your vetinarian in this matter.
Perhaps the best form of training is your attention. A kind word or look from you is the dog’s best reward. When your dog engages in inappropriate behaviour stand still and do not respond. Say “No” firmly when he barks but do not make any other response. Sometimes dogs bark because they have learnt that it gets them attention.