How to set the default font and font size in the composer window
In the Proton Mail(neues Fenster) web app, you can format text for individual emails in the composer window using the formatting ribbon.
You can also specify a default font and font size to be used for all emails you compose.
To set the default font and font size:
1. Log into your Proton Account at mail.proton.me(neues Fenster) and click Settings → All settings → Proton Mail → Messages and Composing → Composing → Composer default font/size.
2. Select your preferred default font and font size from the dropdown lists.