COMPARISON
SnapInk, Apple's built-in tools, or Adobe Acrobat Reader
Apple's built-in tools and Adobe Acrobat Reader both sign a PDF for free, so SnapInk is for the case where the signature on the page has to be the one you wrote in ink — photographed off the paper with a genuinely transparent background, on Android as well as iPhone, with no account and nothing leaving the phone.
This page is about one job: putting your own signature on a document you already have. It is not about sending a document to other people to sign, which is a different job with different requirements — the last section says who does that.
Side by side
| What you want to do | SnapInkiPhone, iPad, Android | Apple's built-in toolsMarkup, and the Preview app since iOS 26 | Adobe Acrobat ReaderFill & Sign, on mobile |
|---|---|---|---|
| Draw a signature on screen | No | Yes, with a finger or a stylus | Yes |
| Photograph a signature off paper | Yes | No | Yes — import an image or use the camera |
| Transparent background on that photograph | Yes | No photograph to make transparent | Not documented by Adobe |
| Scan a multipage paper document | Yes, in the same app | Yes, from Files, Notes or Preview | In Adobe Scan, a separate app |
| Works on Android | Yes | No — iPhone and iPad only | Yes |
| Works without a connection | Yes, at every step | Not stated in the guides below | Yes, for filling and signing, per Adobe |
| Account needed | None | None | An Adobe sign-in is prompted |
| Price to sign | Free, with limits | Free | Free to fill and sign |
What the table leaves out
- Where a cell says something is not documented, it means we did not find it stated in the pages listed at the bottom. It does not mean the feature is missing.
- On an iPhone, signing is part of Markup, which you reach from Files, Mail, Photos and elsewhere; since iOS 26 the Preview app fills and signs PDFs as well. There is no version of either on Android.
- When we installed Acrobat Reader in October 2026 it asked us to sign in to an Adobe account. Other guides say that prompt can be dismissed, so we do not claim the account is required. Acrobat can also keep your signature in Adobe Document Cloud, which is convenient across devices; SnapInk has nowhere to sync it to, by design.
- SnapInk's free tier keeps one signature, allows three exports a month and adds a small watermark. Pro lifts all three. The amounts are on the pricing page, in your own currency.
Which one should you use?
Yes:Use Apple's built-in tools if you have an iPhone and a finger
Drawing your signature on the screen is good enough for most forms, it is free, it is already installed, and nothing will be faster. If that is your situation, you do not need this app, and we would rather say so here than waste your download.
Yes:Use Adobe Acrobat Reader if you want one app for everything PDF
It draws or photographs a signature, it fills and signs offline, and it can carry your signature between your devices through Adobe's cloud. If you already have it, or you need Adobe's other PDF tools in the same place, adding a second app buys you little.
Yes:Use SnapInk if the signature has to look like your pen
The app exists for the signature you wrote on paper: photographed, lifted off the page with a transparent background, and placed so it sits on the document rather than in a white box. It is also the answer if you are on Android, if you scan paper originals and sign them without changing apps, or if you want no account and nothing leaving the phone.
When SnapInk isn't enough
Some documents need more than a picture of your signature. If the document has to prove who signed it — verified identity, a tamper-evident audit trail, or a signing order across several people — then you need an electronic signature service such as DocuSign, and no amount of care with an image will substitute. SnapInk places an image of your signature on a page. It does not verify your identity, issue certificates, keep an audit trail, or send a document to anyone else for signature.
Checked in October 2026
Apps change, and a comparison written once and left alone becomes wrong quietly. These are the pages we read, plus what we tested on our own devices. If something here is out of date, write to support@snapink.ca and we will correct it.
Sources
- Apple — Fill out and sign PDF forms on iPhonesupport.apple.com
- Apple — How to scan documents on your iPhone or iPadsupport.apple.com
- Adobe — How to sign a document on an iPhonewww.adobe.com
- Adobe — Fill and sign forms, Acrobat for Androidwww.adobe.com
- Adobe — Acrobat Reader frequently asked questionshelpx.adobe.com
- Adobe — Scan to PDF with the Adobe Scan appwww.adobe.com
- Mississippi State University IT — dismissing the Acrobat Reader sign-in promptservicedesk.msstate.edu
Try it on the next document
Free to download, and you will know within one document whether a photographed signature is what you wanted. Nothing to cancel if it is not.