According to information obtained by MacRumors, the PencilKit feature appears to work with any text input field available in iOS, making it compatible with Messages, Notes, Reminders, Calendar, Mail, and more. A floating interface will pop up whenever a text field is tapped with the pencil, allowing for the written input.
For example, you could tap into a Messages text field, hand write a message, and then send it to a recipient as regular typed text.
While Apple doesn't have an OCR feature for Apple Pencil input, it does recognize handwritten words in Notes for Search.
The site also reports that third parties may be able to access a PencilKit tool that will support some kind of new handwriting functionality. Additionally, Apple is working on a 'Magic Fill' feature that would allow users to draw a shape and have it automatically filled in.
Apple typically unveils its major mobile software updates at WWDC; however, it's unclear if that event will take place this year due to the coronavirus outbreak. Please download the iClarified app or follow iClarified on Twitter, Facebook, YouTube, and RSS for updates.