How to e-sign a PDF on iPhone for free

The five ways at a glance

For 95% of everyday signing, methods 1 or 2 are all you need. The Adobe and DocuSign apps add audit trails and form-field handling at the cost of installing and (sometimes) creating an account; both are reserved for specific workflows below.

Method 1 — Markup, the built-in iOS signature tool

Markup is the universal annotation tool that ships with every version of iOS from iOS 9 onward, and it has had a dedicated "Signature" pen since iOS 13.¹ It works on any PDF you can open in Mail, Files, Books, Notes, or Photos — which is essentially every PDF on your phone.

Step-by-step (from a Mail attachment)

1. Open the email containing the PDF in the Mail app.
2. Tap the PDF attachment to open it in full screen.
3. Tap the Markup icon in the upper-right corner (a small pen-tip inside a circle).
4. Tap the + button at the bottom right of the toolbar.
5. Choose Signature. If you have a saved signature, pick it; otherwise tap Add or Remove Signature, then +, and draw your signature with your fingertip or Apple Pencil.
6. The signature appears as a draggable, resizable element. Drag it onto the line, resize the bounding box with the corners, and adjust opacity from the colour-picker if needed.
7. Tap Done in the upper-left, then choose to Reply with the signed copy attached or Save File To... if you want to forward it later from Files.

Step-by-step (from Files / iCloud Drive)

1. Open the Files app and navigate to the PDF.
2. Tap to open. Tap the Markup icon in the upper-right.
3. Follow steps 4–6 above. Tap Done to save in place.

The saved signature persists across all of these apps and across reboots. Drawing with the Apple Pencil produces a more legible signature than a fingertip; in either case the result is embedded as a vector shape, not a screenshot, so it scales cleanly when the PDF is printed.

Method 2 — Safari + ScoutMyTool Sign PDF (when Markup is not enough)

Markup is excellent for visually placing a signature on a page, but it does not handle three common situations well: PDFs with interactive form fields you also need to fill, PDFs that come from a website without first downloading them, or PDFs you want to sign without saving an unsigned copy to local storage first. For those, the browser-based path is faster.

1. Open Safari (or any iOS browser) and go to scoutmytool.com/pdf/sign-pdf.
2. Tap to upload — pick the PDF from Files, Photos, or any cloud-storage provider that integrates with iOS Files.
3. Draw the signature with your finger or Apple Pencil in the on-screen signature pad, or type it in a handwriting-style font.
4. Drag the signature onto the signature line, resize, and confirm.
5. Download the signed PDF — it lands in Files / On My iPhone.

Because the entire signing operation runs in the Safari tab using the open-source pdf-lib library, the PDF never leaves your phone. You can confirm this by opening Safari's Web Inspector via the Mac developer tools if you want to verify the no-upload claim.

Method 3 — Filling AcroForm fields before signing

Government and corporate PDFs frequently include interactive form fields — text inputs, checkboxes, dropdowns. Markup can place a signature on top of these but cannot fill them; you need a tool that recognises AcroForm fields. The two free options on iPhone are:

1. Adobe Acrobat Reader for iOS — install free from the App Store, open the PDF, tap the form field, type. Then use Fill & Sign for the signature. Reader does not require an Adobe ID for fill-and-sign, only for cloud sync.
2. ScoutMyTool's PDF Form Fill in Safari at scoutmytool.com/pdf/pdf-form-fill. Same client-side architecture as Sign PDF — no upload, no signup.

For static PDFs without form fields (most contracts, NDAs, and one-off letters), Markup or browser Sign PDF is faster.

Is a signature drawn on a phone screen really binding?

Yes, in the United States and the vast majority of other jurisdictions. The federal ESIGN Act of 2000 (15 U.S.C. § 7001 et seq.) and the parallel state Uniform Electronic Transactions Act (UETA), adopted in 49 states plus DC, establish that an electronic signature has the same legal force as a wet-ink signature for most contracts, provided three conditions are met: (a) both parties intend to sign electronically and consent to electronic records, (b) the signature is associated with the document, and (c) the document is retainable.² Drawing a signature in Markup or a browser tool, then sending the signed PDF, meets all three. The EU eIDAS regulation similarly recognises "simple electronic signatures" for the majority of commercial agreements.³

The narrow exceptions: wills and codicils, certain family-law documents, court filings (depending on local rules), and any document where a specific statute requires a handwritten or notarised signature. For those, the iPhone signature is not enough.

When to reach for DocuSign instead

Three scenarios where a paid signing service is worth the cost even on a phone:

1. Tamper-evident audit certificate required. Lenders, large procurement departments, and some regulators expect a DocuSign or Adobe Sign Certificate of Completion naming IPs, timestamps, and the document hash. A Markup-drawn signature does not produce that artefact.
2. Multiple signers, sequential workflow. If three people in three cities need to sign in a specific order with reminders and re-sends, the DocuSign workflow saves real time. Doing it manually with Markup is technically possible but creates more email threads than it removes.
3. Qualified Electronic Signature under EU eIDAS. A QES — required for some EU public-sector documents — must come from a Qualified Trust Service Provider. iOS Markup is not one. ScoutMyTool is not one. Use the appropriate certified provider for those specific documents.

For everything else — most contracts, NDAs, school forms, waivers, simple invoices, personal property paperwork — the iPhone-built-in or browser-based options are faster, free, and legally equivalent.

Related ScoutMyTool tools and articles

• Sign PDF — works in Safari on iPhone; no app install.
• PDF Form Fill — fill AcroForm fields in the browser.
• Protect PDF — password-protect a signed PDF before emailing.
• Merge PDF — combine the signed contract with attachments.
• Compress PDF — shrink a scan before signing and emailing.
• DocuSign free alternatives — broader signing-options comparison.
• Free NDA template — pair the iPhone signing flow with a template that needs signing.

Frequently asked questions

Is a signature drawn on an iPhone screen legally binding?

Yes, in the United States. The Electronic Signatures in Global and National Commerce Act of 2000 (ESIGN, 15 U.S.C. § 7001) makes an electronic signature legally equivalent to a wet-ink signature for most contracts, as long as both parties consent to use electronic records and the signature is attached to the document. A signature drawn with a fingertip or Apple Pencil in iOS Markup, then embedded in a PDF, satisfies all three requirements. The EU eIDAS framework similarly recognizes "simple electronic signatures" for the majority of business agreements.

Does my PDF get uploaded to Apple's servers when I use Markup?

No. The Markup tool processes the file locally on the device — the editing happens inside the Mail, Files, or Books app and writes the result back to local storage (or, if the file lives in iCloud Drive, syncs through iCloud after the operation completes). No third party other than Apple itself touches the bytes, and if the file is stored locally rather than in iCloud, nothing leaves the phone at all.

Can I reuse the same signature across multiple PDFs without redrawing it every time?

Yes. In Markup, tap the "+" button, choose "Signature", and either pick a saved signature or draw a new one. Saved signatures persist on the device and across the Markup tool everywhere iOS uses it (Mail, Files, Books, Notes, Photos). The same applies to iPadOS. On the macOS side, signatures created in Preview sync to iOS via iCloud Keychain on supported configurations.

What if I need to sign a PDF that lives in Google Drive or Dropbox on my phone?

Download or open the file in the Files app first — both Google Drive and Dropbox integrate as Files providers in iOS 14+. Once the PDF is visible in Files, the Markup workflow is the same. Alternatively, open the PDF in your browser and use ScoutMyTool's Sign PDF tool, which works without installing anything.

How do I share the signed PDF after signing?

For most personal sharing, tap the Share button in Markup or in the host app (Mail, Files, Books) and pick AirDrop, Mail, Messages, or any other share extension. For sensitive documents, password-protect the signed PDF first using ScoutMyTool's Protect PDF tool (also browser-based; runs in Safari on iOS) and send the password by a separate channel. Avoid emailing high-sensitivity PDFs unprotected — your iPhone makes that easy but the risk does not change because the device is small.

Is there a difference between the iPhone signature and a DocuSign signature?

Two differences matter. First, audit trail: a DocuSign-issued signature comes with a Certificate of Completion that names IPs, timestamps, and the document hash; an iPhone-drawn signature comes with no separate certificate, although the email thread containing the signed PDF functions as informal evidence. Second, brand expectation: some counterparties (especially in real estate, lending, and large procurement) expect a DocuSign-branded workflow. For everyday signing, the iPhone signature is legally equivalent and far faster.

Can I sign a PDF on an iPhone without an internet connection?

Yes, with the built-in Markup tool or with Adobe Acrobat Reader once it is installed. Both run entirely on-device and do not need a network connection for the signing step itself. Browser-based tools like ScoutMyTool can also continue running once the page is loaded, but the initial page fetch needs connectivity.