The following post may be helpful, kindly check it out:

Text Classification Using Conditional Random Fields (analyticsvidhya.com)

https://www.analyticsvidhya.com/blog/2018/08/nlp-guide-conditional-random-fields-text-classification/

https://medium.com/data-science-in-your-pocket/named-entity-recognition-ner-using-conditional-random-fields-in-nlp-3660df22e95c

You can use CRF on named entity recognition (NER) for an example. Here is an excellent article to learn CRF in PyTorch: https://towardsdatascience.com/conditional-random-field-tutorial-in-pytorch-ca0d04499463