Individuals and organizations who want to buy a product from a concern or avail services of a firm send enquiries.
Traders send enquiry letters (1) When they want to buy a new kind of goods which they have not been buying or, (2) When they want to renew a contract under revised terms or, (3) When they want to discover new sources of supply. If a trader or a buyer wishes to make the best bargain, he has to begin his exercise with an enquiry letter.