My daughter has seasonally cough from September to March. How it can removed?

I am sorry to hear that your daughter has been unwell. There are a number of reasons why she might be coughing during these months, which I assume for you, is winter:
 
1.    Your daughter may have repeated bouts of viral infections as a result of her immune system being below par

2.    Your daughter may have low grade or latent asthma. This could be made worse with the colder air during winter as well as any upper respiratory tract infection picked up

3.    If your daughter has a tendency to allergies, winter months may mean that she is more likely to be indoors and if she is sensitive to allergens such as house dust mite, her allergy might be manifested as a cough.
 
Of course, there are other possibilities - it is clear to me that the first thing your daughter needs to do is to seek help from a doctor in order to get to the cause of her cough. Only then will it be possible to suggest the appropriate tretament.