Highlights

Highlights is a PDF reader for research that turns PDF annotations into notes. It runs on iPhone, iPad, and Mac, and its free plan includes reading and annotating PDFs, merging annotations, editing PDF metadata, and using Handoff. Notes can be exported in Markdown, TextBundle, HTML, WebArchive, or PDF formats, or sent to supported apps such as Evernote, DEVONthink, Ulysses, Bear, and Keep It. For scientific articles, it can find DOIs, retrieve metadata, and link to a PDF on the device if the citation has already been read. Its on-device multilingual OCR extracts text from PDFs without searchable text. Smart Copy formats copied images as PNG, tables as CSV, and citations as BibTeX. PDFs can be kept on a device, in iCloud Drive, Dropbox, or another sync service; annotations use standard PDF annotations. On macOS, it integrates with Bookends and Papers. Free use is available, and Pro costs $4.99 a month or $29.99 a year, billed monthly, with either option cancelable anytime.

Highlights combines PDF annotation with note exports, citation lookup, and OCR. Its free plan covers core reading and annotation; Pro unlocks everything on iPhone, iPad, and Mac.

Highlights suits students and researchers who work with scientific articles and want to turn PDF annotations into notes. It is also relevant to readers who need exports, citation lookup, or on-device OCR.

Highlights is a research-focused PDF reader that turns annotations into reusable notes. It is most suitable for students and researchers on Apple devices who move material between papers, reference tools and writing apps. Its strongest case is a portable annotation-to-notes workflow; readers wanting automation or broad non-Apple coverage should look elsewhere.

Overview

Highlights combines a reader and editor with annotation, metadata editing and Handoff. The Free plan makes those core PDF tasks available on iPhone, iPad and Mac, including document scanning, Smart OCR and dark mode. That is enough for straightforward reading and markup, while the paid tier targets people who need the complete research workflow rather than a basic viewer.

Key features

Annotations can be merged and exported as Markdown, TextBundle, HTML, WebArchive or PDF. Direct sending to Evernote, DEVONthink, Ulysses, Bear and Keep It is useful when marked passages need to become part of a writing or knowledge system; readers who keep all notes inside the PDF gain less from the subscription.

Citation lookup can find a scientific article's DOI, retrieve metadata and link to a locally stored PDF when that citation has already been read. Multilingual OCR runs on the device and extracts text from PDFs without a searchable layer, which is valuable for scanned papers and keeps processing local. Smart Copy outputs copied images as PNG, tables as CSV and citations as BibTeX, reducing cleanup when transferring research into other formats.

Files can stay on the device, in iCloud Drive, Dropbox or another sync service. Because annotations are stored as standard PDF annotations, marked files remain usable outside Highlights. On macOS, Bookends and Papers integration fits established reference-management setups. The trade-off is that Highlights is not scriptable, so it is a poor choice for readers who require automated actions or custom processing.

Pricing

The Free plan costs nothing and includes reading and annotating PDFs, metadata editing, Handoff, document scanning, Smart OCR and dark mode. It suits readers who need dependable Apple-device markup without a subscription.

Pro Monthly costs $4.99 a month, billed monthly, with cancellation anytime. Pro Annual costs $29.99 a year, also described as billed monthly, with cancellation anytime. Both Pro plans unlock everything on iPhone, iPad and Mac, making them the fit for users who need the full export, citation and OCR workflow across devices. The free trial lowers the risk of deciding, while the free tier remains the better value for occasional annotation.

Platforms

Highlights supports iPhone, iPad and Mac, with cross-platform access across those Apple devices and offline use. Storage can be local or connected to iCloud Drive, Dropbox or another sync service. The Apple-only footprint rules it out for readers who need Android or Windows clients.

Who it's for

Students, academics and researchers who read scientific literature and turn highlights into notes are the natural audience. It is also a strong fit for anyone already using Bookends, Papers or one of the supported note apps. Choose another tool if broad operating-system support, scripting or a conventional general-purpose PDF utility matters more than research-oriented exports.

Pros and cons

Pros

• Research-ready exports: Multiple note formats and direct app destinations make annotations usable beyond the original PDF.
• Useful scientific tools: DOI lookup, metadata retrieval, BibTeX copying and multilingual on-device OCR address common academic-document chores.
• Portable files: Standard PDF annotations and flexible storage reduce dependence on one library.
• Privacy-minded use: Personal information is not required, optional annotation usernames stay local, and payment or licensing information is not collected.

Cons

• No scripting: Automated or highly customized workflows are not supported.
• Apple-only platforms: Android and Windows users cannot use the app as a primary reader.
• Full workflow is paid: Users who need every feature across devices must move beyond the Free plan.

Alternatives

Foxit PDF Reader is the better choice for broad Android, iOS, macOS, web and Windows coverage, with a free reader that includes viewing, printing, annotation, collaboration, form filling and signing.

KDAN PDF suits readers wanting Android, iOS, macOS and Windows support with free basic editing, annotation, handwriting and signatures.

MuPDF is an option when Linux, web or self-hosting is important; its listed Commercial plan is $299 a month.

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

StarForce Reader is a free option spanning Android, iOS, Linux, macOS and Windows.

Kiosk is a free, open-source PDF reader with no paid plans.

Adobe Scan is worth considering when mobile document scanning is the priority on Android or iOS.

GoodReader is a paid iOS and macOS PDF reader and file manager with optional Pro Pack subscriptions.

For a broader starting point, browse the PDF Readers list.

Verdict

Choose Highlights if you are an Apple-based student or researcher who wants annotations to flow into notes, citations and reference tools, especially with on-device OCR. Its main reason to look elsewhere is the combination of Apple-only platforms and no scripting; readers needing wider device support or automation will be better served by another PDF reader.