Hi,
I am not sure which package the classify_emotion and classify_polarity belong but typing the following in the terminal will give you the function help and examples.
?classify_emotion
In my experience, I have used packages like "tidytext" and "sentimentr" to complete various NLP related tasks.
Within "tidytext" there is a function "get_sentiments(lexicon="nrc")" which will give you the emotion for the texts.
For polarity and subjectivity related tasks, kindly also check the python package "TextBlob".
With the super interoperability of R & Python code within the RMarkdown document, you can use "TextBlob" within RStudio itself.
Best wishes.
Vinay