"Epistolize" Natural Recordings by Native Speakers
To epistolize means to write a letter or write in the form of a letter; characterized by the style of letters, especially in being formal, polite, and informative. It can also refer to the act of exchanging letters.
Epistolic refers to something related to epistles, which are formal letters or messages, typically formal or official in nature. In a broader sense, epistolic can also describe something that is characteristic of letters or messages, such as their written form, tone, or style.