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PDF Duo 1.0
PDF Duo is a free PDF reader for iPhone, designed for iPhone Duo and foldable iPhones. Here is how to do the common things.
Open a PDF
Open it from the Library, or connect iCloud Drive or any folder once so its PDFs show up there. From another app, use Share › Open in PDF Duo.
Read like a book
Open your iPhone Duo on its side: two pages sit across the fold and turn with a page curl. Closed, open upright or half open, you stay on the same page.
Sign and fill
Tap Fill and sign. Fill fields one by one with Next field, sign with your finger, and send a flattened copy so nothing can be changed. The signature is handwritten and placed on the page, not a certificate-based digital signature.
Mark up
Run your finger along text to highlight it; underline and strike through the same way. Pen, text boxes, notes and shapes are in Mark up. Undo anything.
If the app quits
Unsaved changes come back the next time you open the document.
Not yet
Editing a PDF's existing text or images, certificate-based digital signatures, and Apple Pencil on iPhone Duo.
Still stuck, or found a bug? Contact Alano, the maker of PDF Duo.