Policy, offer and other documents?

Question

Law in IT

I constantly see different documents on the websites of competitors, one has such documents, the other has others, and the topics are the same ...
Explain what they mean, so to speak, in simple terms)

• privacy policy
  
• offer
  
• Terms of use
  
• cookie policy
  
• protection of personal information
  
• Terms of use
  

and which ones should be used on a book selling landing page, where the buyer leaves his data?