Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
This question already has an answer here:
Can I make a list of people who send me mail in gmail?
If so, How Can I do that?
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
You can use Google Scripts to extract email addresses from Gmail.