Hey, everyone. I am sure several people have asked this question, yet I was unable to find their posts. In the salutation of an informal letter, how should I use a comma? For example, should I write Hey, Frank, How have you been? or Hey Frank, How have you been? Or should I not even use a comma? I understand that grammar is not so important in an informal letter, but I still wish to write correctly. Thank you for your time.