This feature has already been logged into our issue tracking system as SAASWORDS-204 but unfortunately it has not been implemented yet. Although this feature has a high priority but there are some limitations which are restricting us from implementing it.
Our product team is working on resolving all related issues to implement this feature in near future. We will keep you updated on this issue in this thread.
In latest release of Aspose.Words Cloud, we can use custom fonts in Word to PDF conversion. You can upload your custom fonts to a cloud storage folder and pass its path in fontsLocation query parameter in the conversion request call. Please feel free to contact us if you face any issue in this regard.