A stopword list is a set of words that should be excluded from the results of a tool. Typically stopword lists contain so-called function words that don’t carry as much meaning, such as determiners and prepositions (in, to, from, etc.).
Voyant is a web-based tool. To use it go to http://voyant-tools.org. This is what you will see, To use Voyeur you need to specify a text. You can do this different ways: Type the text into the field and then