'Inquire' and 'enquire'

There is no difference, and both means 'to ask for information'. 'Inquire' is more common in American English, while 'enquire' is more common in British English.



 Eva inquired about the progress of the project. (American English)
 Eva enquired about the progress of the project. (British English)

Similarly, 'inquiry' and 'enquiry' means the same thing: (the process of) asking a question.