iAnnotate for Android – Annotate & Share PDFs
iAnnotate is a free Android app for drawing, highlighting, and typing on top of PDFs that you access on your Android tablet or phone. In a classroom setting iAnnotate could be used by students to highlight important passages or ask questions about a passage in a document that you’ve shared with them. For example, if I share the text of a primary source document with students I could have them use the app to insert their questions about the document.
From a workflow perspective iAnnotate could be handy when someone sends you a document that requires a signature as you could simply open the app then sign the PDF and send it back.