If you would like to send your boss a personalized letter on his birthday, here is a template you can use to write a happy birthday letter for your boss.
Dearest [name],
If there is one thing I learned during my time of working in this company, it is the fact that they have a great owner. Not only do you do a good job of encouraging the people under you, you also do great in promoting the company’s goals. There is no doubt the company would not be where it is now if you are not the boss.
The last thing I want to see is you having any difficulties with your job. I know how it is like to get stressed out. Thus, feel free to approach me if you want to do less work today. Besides, you deserve having the best birthday ever today.
Sincerely yours,
[name]