The two words "query" and "inquire" are called synonymous. They essentially mean the same thing, the main difference is in their common uses in British and American English, the British tend to use the word enquiry when they are asking for information and the word inquiry in more formal settings. Request means asking, in business English, for example : "I requested you to inquire about the meeting date" means "I asked you to find out about the meeting date" Hope that helps!