Here's a breakdown:
Enquiries:
* More common in British English.
* Focuses on formal requests for information or details.
* Often used in business contexts.
* Example: "We received several enquiries about the new product."
Inquiries:
* More common in American English.
* More general and can refer to any kind of investigation or search for information.
* Can be used in both formal and informal contexts.
* Example: "The police are conducting inquiries into the robbery."
Essentially, "enquiries" emphasizes the act of requesting information, while "inquiries" encompasses a broader range of investigations.
In most cases, either word can be used and will be understood. However, if you're writing for a specific audience or in a specific context, it's a good idea to consider the regional variations and the connotations of each word.