____________ (Name of the Teacher)
I hope you are doing well. Well first, wish you a very happy birthday, may the Lord Almighty shower all the blessings upon you. This being a very special day, I would like to tell you one thing; you have been consistent support throughout my school life. It is a blessing for me that I got you as my teacher, as my supporter. Not only me, I believe that everyone you have taught shares the same thought.
I would definitely keep in you in my prayers throughout my life and ask the almighty to bless you with grace. Always keep up the beautiful smile you have received as a gift and keep the healthy spirit high in your life. You have worked hard to achieve milestones and I pray that you may never stumble in your life. Once again, wishing you an amazing birthday, this being your day, enjoy it to the fullest.
With lots of love,
__________ (Name of the Student)