Hi [Insert manager],
I wanted to let you know that I have been accepted into the [Insert course] course at [Insert university] and planning to attend later this year.
As it has always been on my mind to pursue a [Insert higher education], I hope my decision is one you can understand.
Let me know if you have a quick second to chat today and I can provide more details and also discuss if there will be anything I will need to transition over to my colleagues in the next few months.
Thank you!
‍
Best Regards,
[Insert Signature]