Dear HR and Manger
I don't like this kind of email when I'm writing it.
I would like to inform all and I would like to say, Thank you for the time and effort you spent considering me for a position as Design Engineer.
I appreciate your time and effort. I'm grateful for your effort.
It was a difficult decision to make, but, I have accepted another opportunity that's more in line
with my skill and career goals and salary more.
Again, thank you for your time and consideration.
If you have any question, Please contact me by email only krub.