Now students can add their ideas — and write outside the lines — by annotating documents in the mobile app. (50thingsbook.com)
XHTML Content Documents also include the means of annotating document markup with rich metadata, making them more semantically meaningful and useful both for processing and accessibility purposes (XHTML Semantic Inflection [Content Docs 3.1]-RRB-. (idpf.org)
Forget drawing: Want to take notes on your iPad or annotate documents with the Apple Pencil? (imore.com)