How To Annotate PDF Online?
Upload & Edit Your PDF Document
Save, Download, Print, and Share
Sign & Make It Legally Binding
Easy-to-use PDF software
What kind of program language would I need to build an application to annotate and pull text from PDF files and webpages?
Take a look at Enfocus Pitstop. It can edit just about anything you might need to edit but it requires that you have full Online Pdf Annotator . Edit PDF Files with PitStop Pro Software | Enfocus
Annotate PDF: All You Need to Know
You can also find some more great PDF viewing and editing program on iOS store.