Main ways of communication of dogs:
Barking:

A dog may bark to warn of danger, attract attention, or express excitement.
howls:

Howling can be a sign of loneliness, discomfort or a desire to attract attention.
body language:

Dogs use body postures, tail movements, facial expressions and more to convey their mood. For example, a raised tail can indicate joy, while a folded tail can indicate fear.
facial expressions:

Dogs can show signs of fear, joy or sadness through their facial expressions.
Contact with humans:

Dogs are able to understand verbal commands and recognize human emotions, which strengthens the bond between them and their owners.

. body language
Body Postures: A dog may stand up straight and approach when it feels safe, while when it is afraid, it will shrink and curl inward.
Tail movements: An upright tail moving from side to side can indicate joy or excitement, while a folded tail between the legs indicates fear or anxiety.
Facial Expressions: Dogs can show emotions through their facial expressions. For example, wide eyes may indicate apprehension, while a smile (when lips move) may indicate happiness.

2. Voices
Barking: A dog may bark to alert you to something, ask for attention or express excitement. Each bark may be different depending on the situation.
Howling: Howling can indicate loneliness or a desire for attention. Dogs also howl to communicate with other dogs.
Purgs or grunts: These may indicate comfort and contentment, especially when the dog is being comforted or playing.
3. Eye contact
Dogs can make eye contact with humans to ask for attention or communicate feelings. Prolonged eye contact can show trust and emotional connection.

4. Non-verbal body movements
Dogs may rest their heads on their owners' knees or approach them to ask for affection or attention. They may also show signs of excitement when they see their owner.
5. Learning and understanding of commands
Dogs can learn to recognize and follow verbal commands. They are able to understand not only the commands themselves, but also the tone in which they are spoken to. A positive tone can encourage them, while a negative tone can make them feel scared or stressed.

6. Response to emotional stimuli
Dogs are very sensitive to human emotions. They can recognize when their owners are sad, stressed or happy, and sometimes they will even react accordingly - for example, they will come closer and comfort when there is sadness.
In conclusion
Dogs are very intelligent animals that can communicate very well with humans. They use non-verbal language, sounds and emotion to build deep bonds with humans, making them loyal friends and beloved family members.