Show your employer how the course is directly related to your job requirements and responsibility by explaining in a brief essay how it contributes to your professional development.
Tell your employer how the course will benefit the company and improve your job performance. Explain how the course will bring education that can't be received only by working in your position.
Assure your employer that the time required to take the course will not impact your job performance negatively. If the course requires you to miss work, explain how you will make up the missed time.
Provide copies of all necessary documentation regarding tuition expenses, enrollment fees, school or course accreditation, and the content covered in the course.
Present your complete case in a timely manner, preferably before you take the course, so that if your claim is denied, you can decide to withdraw.