I have an S5 and trying to change the font of emails from my Samsung device to Outlook. How can I do this?

[AC Question]

I have an S5 and trying to change the font of emails from my Samsung device to Outlookk.

I have downloaded an app to change the font (other than the normal four options) but the emails I receive on my Outlook still the common front which is default by Samsung S5. Is this a device issue or an Outlook issue?