Extract imperative sentences from a document(English) using NLP in python
In order to maximize accuracy you would need to use not only a POS tagger but also a syntactic parser. Nevertheless for this task POS tags can probably give you reasonable results indeed, here is a general method:


Segment the data into sentences and tokens
Apply the POS tagger (it predicts a POS tag for every token)
A sentence is (likely) imperative if the following conditions are satisfied:


the sentence ends with a full stop or exclamation mark
the POS for the first token corresponds to a verb



This heuristic is probably all you need, but if you want to go further you could generate instances containing these features (and possibly add a few others)  for every sentence, annotate a training set and train a supervised model.