How to change the font of Whatsapp I was looking for a way to add custom emoticons to Whatsapp, and since this method simply replaces existing emoticons with new ones I thought about replacing characters from a language I won't use (for example Tangut, the language this iOS app used) with the desired emoticons

I wanted to know how to replace some (or all) of the characters of said language in Whatsapp using a changed font that could be installed on other phones as well
Just go to settings in your phone and change the font style.
It will change the font style in whatsapp but not the message font. You can also try installing other keyboards from Google play store with different font styles, emoticon and other languages.