Overview

The free plan covers viewing, annotation, handwriting, signatures, and filling existing forms. That is a useful set for reviewing and returning paperwork, but the omissions matter: free users cannot edit PDF text, create forms, run OCR, or convert PDFs. KDAN PDF is therefore a capable starting point, not a no-cost substitute for a full editing workflow.

KDAN PDF is powered by KDAN Mobile Software Ltd., founded in 2009 and based in Tainan City, Taiwan. The software is described as GDPR-compliant. Its lifetime desktop license supports offline work without cloud uploads, a practical distinction for users who want to keep documents local.

Key features

Reading and document work

Annotations, notes, handwriting, signatures, and form filling make the free tier useful for reviewing documents and completing paperwork. Paid plans add text editing, merging and splitting, Office-file conversion, and OCR that turns scanned PDFs into editable, searchable documents. Those additions make a subscription a better fit for people who regularly revise PDFs or work with scans; occasional readers can avoid paying.

AI and accessibility

Document 365 AI+ adds AI auto-redaction, summarization, document review, and paragraph translation. KDAN PDF also offers extraction, document chat, and translation among its AI capabilities, while paid plans include read-aloud text-to-speech. These tools are relevant to users handling lengthy or multilingual documents, but they sit behind the more expensive subscription.

Pricing

KDAN PDF Free: 0.00 USD per free. It includes viewing, annotation, handwriting, signatures, and form filling. Choose it for reading and completing existing paperwork; it gives up text editing, form creation, OCR, and conversion.
Document 365: 59.99 USD per year, billed annually. It unlocks features across Android, iOS, Mac, and Windows, including text editing, merging and splitting, Office conversion, OCR, and password protection. A seven-day free trial gives users a short evaluation window. This is the sensible paid tier for document editing without the AI package.
Document 365 AI+: 99.99 USD per year, billed annually. It includes Document 365 features plus AI services such as auto-redaction, summarization, document review, and paragraph translation. The higher price makes sense mainly for users who will use those AI tools.
Lifetime License: 119.99 USD per once for a permanent license on one device. It is a desktop option for someone who prefers a one-time purchase and offline work, but it is limited to one device rather than the multi-platform coverage of Document 365.

Document 365 and Document 365 AI+ have seven-day free trials. Refunds can be requested within 14 days of purchase, subject to store exclusions. Credit cards and PayPal are accepted; wire transfer is available for business and volume purchases.

Platforms

KDAN PDF supports Android, iOS, Mac, and Windows. Document 365 covers all four; the lifetime license is for one desktop device. The software supports English and several major Asian and European languages.

Who it's for

Choose KDAN PDF if you need a cross-platform way to read, annotate, sign, and fill forms, or if you want a paid path to OCR and PDF editing. It is less suitable if you need those editing tools at no cost, or if AI is not worth the premium over Document 365.

Pros and cons

Pro: The free plan handles reading, markup, signatures, and form completion, so routine paperwork does not require a subscription.
Pro: Document 365 combines editing, OCR, conversion, and password protection across four platforms.
Pro: The one-device lifetime desktop license supports offline work without cloud uploads.
Con: The free tier excludes text editing, form creation, OCR, and conversion, limiting it to basic document tasks.
Con: The lifetime license covers only one device, while the annual plans are needed for access across Android, iOS, Mac, and Windows.
Con: AI tools require the higher-priced Document 365 AI+ plan.

Alternatives

Foxit PDF Reader is worth considering if free viewing, annotation, collaboration tools, and form filling are your priority.

MuPDF is another freemium option, with support across mobile, desktop, web, Linux, and self-hosted platforms.

Highlights may suit Apple users who want free annotation, metadata editing, scanning, and Smart OCR on iOS or macOS.

Javelin PDF Reader is a free reader for Windows, macOS, iOS, and Android.

StarForce Reader is a free alternative available on Android, iOS, Linux, macOS, and Windows.

Kiosk is a free, open-source PDF reader.

Adobe Scan is a mobile option for Android and iOS.

GoodReader is an iOS and macOS PDF reader and file manager.

Browse more PDF Readers or PDF editors.

Verdict

KDAN PDF is a strong fit for readers who want free markup and form-filling across mobile and desktop, with a clear upgrade path to OCR and editing. Choose Document 365 when those paid tools are part of regular work, or the lifetime license when offline desktop use on one device matters most. Look elsewhere if you need editing features without a subscription or want AI capabilities without the AI+ premium.

	Aiseesoft Free PDF Viewer	KDAN PDF
Free plan	Yes	Yes
Free trial	No	No
Paid from	Free	$5/mo
Open source	No	No
Platforms	Windows	Android, iOS, macOS, Windows
Free plan	Yes	Yes
Platform support	desktop	—
Annotation tools	—	Yes

Aiseesoft Free PDF Viewer vs KDAN PDF

Aiseesoft Free PDF Viewer

KDAN PDF