dopisivati

1. (dopisivati se s kim) to correspond; to text each other
   Dopisujemo se preko Vibera skoro svaki dan. — We text each other on Viber almost every day.
   Godinama se dopisivala s drugaricom iz Kanade. — For years she corresponded with a friend from Canada.
2. to add in writing
   Stalno dopisuje napomene na marginama. — He keeps adding notes in the margins.

In the sense 'to correspond' it takes se and s + instrumental: dopisivati se s nekim.