Required reading

• Chapter 14 or R for Data Science by Garrett Grolemund and Hadley Wickham.
• Chapter 1 of Text Mining with R by Julia Silge and David Robinson.

Optional reading

If you want more indept information about what is happening with regards to using text as data, tokenization, stopwords etc. Then you can look at the first 4 chapters of Supervised Machine Learning for Text Analysis in R by Emil Hvitfeldt and Julia Silge.