Voyant Tools, created by Stéfan Sinclair & Geoffrey Rockwell, is "an open-source, web-based application for performing text analysis. It supports scholarly reading and interpretation of texts or corpus, particularly by scholars in the digital humanities, but also by students and the general public. It can be used to analyze online texts or ones uploaded by users." ("Voyant Tools", 2020)
The program will automatically determine word frequencies and colocates and display them graphically.