Hello. You did not present the text to which this question refers, which makes it impossible to formulate an answer exactly, but I will try to help you in any way I can.
The tone of a text presents the feeling and sensation that the author passes on to the reader through it. In this case, the use of words must be well thought out, as they are the ones who will achieve this goal. In this case, if the author uses elaborate words he wants to establish a formal tone, if he presents imperative words, the author is trying to convey an authoritative one, the author can even use emotional words presenting an emotional tone and so on.
In other words, to answer this question, you must observe the nature of the words presented in the text you have.
