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While you wait for one of our customer support representatives to get back to you, please check out some of these documentation pages:
Guides:- Best practices for PDF.js Express - Store annotations
- Saving a document with annotations
- XFDF format - In PDF.js Express Web Viewer
- How to render xfdf back into pdf
- How to show the annotation on the PDF with selected xfdfString
- How to set Note(‘stickyToolGroupButton’) annotation to custom button
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