I have been developing custom keyboard with TrueTypeFont. I have successfully installed font on iOS through apple configurator 2 which is signed. I have tried a lot search for changing input text font same as keyboard font.
I have followed this link for generating signed mobiconfig file with font payload.
Apple Configurator 2 for generating file. Sign in code using File->Sing in and select certificate for which you're trying to get verified.
I'm looking for changing font system wide not in particular app for input like textfield or searchbar or anywhere we type something in any application.