In a 2018 WORDS ON THE LINE 14-part series on tone, which I'll summarize here, I showed how you can look at tone from many persepectives.
A good start is to define tone, which I see as the writer's attitude about the message, the reader, or both. Next, consider the consequences of a bad tone, which can ultimately escalate to losing your job. (I know of instances when it happened.) Then consider the many influences on tone, including those you can control and those you have little control over. Finally, practice ways of checking your tone, which may mean whether to respond at all and when to respond. Coming into play are word choice, salutations, complimentary closings, opening and closing sentences, sometimes apologizing, avoiding negative language, making your words and not emojis speak for you, and maintaining positive relationships.
It may be true that tone is not about what you say but how you say it, but when it comes to writing, the words we use substitute for our speaking voice. So watch what you write.
