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Direct answers to real iPhone PDF questions, with the screen you need at every step.

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PDF SIGN & SCAN A real PDF Sign & Scan workflow: open a PDF, choose a saved signature, place it, and share the signed copy

Capture your handwriting

PDF Sign & Scan capturing a real handwritten signature and removing the paper background

01How to add a handwritten signature to a PDFUse a signature you wrote on paper—not a script font or a rushed finger drawing—and place it cleanly on a PDF.

The Scan Your Signature screen in PDF Sign & Scan with a cleaned signature preview

02How to scan a signature from paperPhotograph your signature on paper, remove the background on your iPhone, and save clean ink for PDFs.

A photographed signature cleaned and saved in the PDF Sign & Scan signature library

03How to save a signature from a photo on iPhoneUse a photo you already took, remove the paper background, and keep the cleaned signature in an on-device library.

Paper handwriting being cleaned into a reusable signature on iPhone

04How to create a handwritten signature on iPhoneScan the signature you write on paper or draw one on screen, clean the result, and save it for PDFs.05How to scan and sign a document on iPhoneTurn a paper document into a PDF, place your saved handwritten signature, and share one signed file from your iPhone.06How to sign a scanned PDF on iPhoneAdd a saved handwritten signature on top of a scanned PDF page without converting the scan to editable text.

Clean and save it

The PDF Sign & Scan signature library where a saved signature can be exported as PNG

01How to make a transparent signature PNGRemove the white box behind a photographed signature, preserve the ink edges, and export the cleaned handwriting as a transparent PNG on iPhone.

The Saved Signatures picker in PDF Sign & Scan

02How to save and reuse a signature on iPhoneCreate a named signature once, keep it in your on-device library, and place it on future PDFs without drawing it again.

Paper signature cleaned and saved with blue ink for a PDF

03How to make a blue handwritten signature for PDFScan your handwriting from paper, clean the background, save the ink in blue, and place it on a PDF from your iPhone.

Before and after view used to clean a blurry handwritten signature

04How to fix a blurry signature in a PDFRe-capture a soft signature, preserve fine strokes during cleanup, and avoid enlarging it past its useful size.

Place it and send

01How to sign a PDF on iPhoneOpen a PDF, add your real handwritten signature, resize it, and share the signed copy from your iPhone.02How to sign a PDF without printing itSkip the print-sign-scan loop. Add your saved handwritten signature directly to a PDF and share the signed copy.03How to sign a PDF from Mail or Files on iPhoneMove an email attachment or saved PDF into PDF Sign & Scan, add a signature, and return the signed copy.04How to sign a PDF from Gmail on iPhoneOpen a PDF attachment from Gmail, add your handwritten signature, and send the signed copy back from your iPhone.

PDF Sign & Scan removing the paper background from a handwritten signature image

05How to add a signature image to a PDF on iPhoneTurn a signature photo into clean transparent ink, place it over a PDF, and avoid the white rectangle behind it.

A handwritten signature positioned across pages of a PDF on iPhone

06How to sign multiple pages in a PDF on iPhoneAdd a saved signature to several PDF pages, copy its placement when useful, and review every page before export.

Handwritten signature being resized and positioned on a PDF page

07How to resize a signature in a PDF on iPhoneMove and pinch a handwritten signature until it fits the signature line without covering nearby text.08How to share a signed PDF from iPhoneExport a flattened signed copy, verify it, and send it through Mail, Messages, WhatsApp, AirDrop, or Files.

Documents and situations

01How to sign a contract on iPhoneOpen the contract PDF, add your real handwritten signature, verify the document, and return a signed copy without printing.02How to sign a PDF from WhatsApp on iPhoneOpen a PDF received in WhatsApp, add your saved handwritten signature, and send back a flattened signed copy from your iPhone.03How to sign a lease PDF on iPhoneKeep the original lease, place your real handwritten signature on the correct page, and return a checked signed copy.04How to sign a permission slip on iPhoneSign a PDF permission slip received by email or message and return a clear copy without printing it.05How to sign a consent form on iPhoneReview a completed consent-form PDF, add your real handwritten signature, and send back a verified signed copy.

Fix signing problems

01Why can’t I sign a PDF on iPhone?A PDF may open but still refuse a signature because it is in a limited preview, permission-locked, already certified, or not the file you thought you saved. Use these checks before changing the document.02Why does a PDF signature disappear after saving or printing?A signature can vanish because the wrong copy was opened, an annotation was not committed, a viewer hides a layer, or print settings omit markups. Diagnose the file without damaging a digital signature.03How to sign a locked PDF on iPhoneBefore signing a locked PDF, identify whether it has an open password, editing restrictions, or an existing digital certificate. The safe next step depends on the lock.

Understand signatures and files

01Electronic signature vs. digital signatureUnderstand the practical difference between a visible electronic signature and a certificate-based digital signature before signing a PDF.02Apple Markup vs. a PDF signature app on iPhoneUse the free built-in tool for a quick finger-drawn signature. Use a dedicated app when you need handwriting from paper and a reusable library.03What is a scanned signature?A scanned signature is an image of a mark first written in ink on paper. Here is what the file contains, what it can prove, and when to ask for another signing method.04Scanned signature vs. digital signatureA scanned signature reproduces handwriting; a digital signature uses cryptography. Compare appearance, identity checks, document integrity, and practical use.05Electronic signature vs. handwritten signatureCompare an electronic signature with ink written on paper, including how each is created, delivered, stored, and accepted.06How to sign a PDF without an account on iPhoneCompare account-free ways to sign a PDF on iPhone: Apple’s built-in tools, a device-local signature workflow, and the privacy questions to ask before uploading a document.07How to protect a signature image in a PDFReduce casual reuse of a signature image by controlling the source file, sharing a final PDF instead of a loose PNG, and understanding what flattening can and cannot protect.08Signature PNG vs. JPG for a PDFPNG keeps transparency and sharp ink edges; JPG is designed for photographs and can add a white rectangle or compression artifacts around handwriting.09What size should a signature image be for a PDF?There is no universal signature pixel size. Start with a clean source, place it at the document’s signature-line width, and check the exported PDF at normal zoom.10What is a PDF signature stamp?A PDF signature stamp is usually a reusable visual mark placed on a page. It may contain handwriting, text, or an approval label, but it is not automatically a certificate-based digital signature.11How to check whether a PDF is signedA visible handwritten mark answers a different question from a validated digital signature. Check the page appearance, reopen the exact file, and use a signature panel when certificate proof matters.