1. School: Schools need to buy textbooks, reference books, novels and other different types of books for students to learn to read.

2. Public libraries: Public libraries need to purchase all kinds of books to meet the needs of readers in knowledge, culture and entertainment.

3. Enterprises: Enterprises need to purchase all kinds of professional books to improve the professional skills and quality of employees and support the development and innovation of enterprises.

4. Government agencies: Government agencies need to buy various books on law, economy and management to help government workers understand relevant policies and regulations.

5. Research institutions: Research institutions need to purchase various academic works, research reports and professional magazines to support researchers' academic research and publication.