Dear Mr. Headmaster of Vinh university,

My name is [...].  I am writing to ask you to let me join an English course to improve my listening and speaking skills. I want to ask you about the fee, is it expensive? And also, what time does the class start and finish? And at the end of the term, does the class have an exam? I really hope to improve my listening and speaking skills so that I can get 8.0 IELTS. Look forward to your help!

                                                                                                                       Sincerely,

                                                                                                                   [your signature]                                                                 

Dear Principal of Vinh University.
Dear Principal, Vinh University.
My name ... I want to register for an English course so that I can improve my listening and speaking skills. And let me ask if the tuition here is high, when is the time to start this course and when is the end time? If possible, I hope I can apply for this school!
We look forward to the help of everyone

Study well !