For Xodo to recognize your personal font file, please place it into the following folder: /storage/emulated/0/Download/Xodo. An easy way to access your device's folders is by plugging your device into a computer or by downloading a file management app, such as Cabinet. Xodo will only recognize True Type Font (.ttf) or OpenType Font (.otf) font files.
Xodo will use this font for substituting fonts within the document (when the font is not embedded in the PDF) and within free text annotations. To check if Xodo is recognizing your font file, create a free text annotation and change the font of the text annotation to the font you just added. Check out this guide for steps on how to change the font of a text annotation: http://feedback.xodo.com/knowledgebase/articles/826002-changing-the-font-of-a-text-annotation.
Please feel free to contact support at firstname.lastname@example.org if you are having any troubles.
Changing the font of a text annotation
Controlling the list of available fonts
Creating a text markup annotation