Change 'Compose' font form iPhone App

Hi, I recently change my smartphone from Android to iPhone. I cannot set the font used to compose emails from the Zoho Mail App. In the Android App, I remember using 'Sync other Desktop Setting' and the font used was the same set as default from the web-based platform. I've tried changing the 'Default Font When Composing' option but it only displays Verdana font when composing from iPhone. Thank you for your help.