Microsoft is closing a stubborn mobile productivity gap. In August 2026, the OneDrive apps for iOS and Android will let authorized users annotate PDF files that carry Microsoft Purview sensitivity labels—preserving the labels’ encryption and making it safe to highlight, comment on, and draw on sensitive documents right from a phone or tablet.
The change, published on the Microsoft 365 Roadmap, addresses a long-standing limitation: until now, protected PDFs could only be viewed in the mobile apps, with any markup tools disabled. For the millions of enterprise workers who rely on sensitivity labels to safeguard confidential documents, that meant either printing, unprotecting, or switching to a desktop machine just to add a signature or circle a paragraph. Next year, those workarounds go away.
What’s Changing — and When
The update delivers a simple but powerful new capability. Once available, opening a sensitivity-labeled PDF in the OneDrive mobile app will present the full annotation toolbar familiar from unprotected files. You’ll be able to add sticky-note comments, highlights, underlines, freehand ink, and text boxes, all while the file’s encryption remains intact. The app will save your annotations and leave the Purview label unchanged, so the document stays protected throughout its journey.
| Annotation Type | Supported |
|---|---|
| Text highlight | Yes |
| Freehand pen/ink | Yes |
| Sticky note comment | Yes |
| Underline and strikethrough | Partially (depends on label policy) |
| Form field entry | No |
| Page reordering | No |
| Redaction | No (requires dedicated tool) |
Microsoft hasn’t confirmed every tool that makes the cut, but early roadmap signals indicate a core markup set focused on review workflows rather than full document engineering. You’ll still need Adobe Acrobat or a similar editor if your work demands advanced PDF manipulation.
The rollout is timed for August 2026, with general availability expected worldwide. It will work for labels applied to PDFs stored in SharePoint libraries and OneDrive for Business, provided your organization uses Microsoft Purview Information Protection. The feature will be built into the standard OneDrive app—no extra plugins or subscriptions required—though you’ll need the latest version from the App Store or Google Play when the time comes.
Who Benefits — and Who Doesn’t
If you use OneDrive with a work or school account that enforces sensitivity labels, this is a game changer. Imagine an attorney who needs to redline a draft contract while commuting, or a compliance officer checking a report from a hotel room. Instead of wrangling with desktop-only tools, they can stay in the flow on their iPad or phone.
For IT administrators, the benefit is equally clear. “How can I annotate a protected PDF?” has been a top friction point for Microsoft 365 mobile users. By baking the capability directly into OneDrive, Microsoft removes the need for risky workarounds—like downloading a file to an unmanaged device, printing a hard copy, or, worse, stripping the label entirely. It’s a win for both productivity and security posture.
Home users with a Microsoft 365 Personal or Family subscription won’t see this feature. Sensitivity labels are an enterprise-grade feature tied to Microsoft Purview, which requires an E5 license or an add-on. If your OneDrive files aren’t labeled, you’ve been able to annotate PDFs in the app for a while (though with a simpler toolset). The new capability is aimed squarely at the business audience.
The Long Road to Mobile PDF Security
Microsoft’s journey toward mobile document security has been incremental. Purview sensitivity labels—formerly Azure Information Protection—have been available for PDFs in OneDrive since 2020, letting users assign encryption and permissions. But those protections came with a sacrifice: on mobile, viewing was all you could do. Annotation required the full Acrobat desktop app or a third-party tool that could handle encrypted MSIP labels, and those were rare.
That gap became more glaring as mobile devices grew into primary work tools. A 2023 Forrester report noted that 60% of information workers use a smartphone for at least some part of their daily document tasks. Yet sensitive PDFs remained a dead end on these screens. Other cloud storage services like Box and Dropbox offered basic mobile PDF annotation but struggled to support Microsoft’s proprietary sensitivity-label encryption. This left Microsoft’s own app lagging its own security promise.
Timeline of key milestones:
- 2020: Sensitivity labels introduced for PDFs in OneDrive and SharePoint.
- 2021: Mobile apps gain the ability to view labeled PDFs, but without annotation.
- 2023: Sensitivity labels extend to Teams mobile chat and channels.
- 2025: Enhanced label management dashboard rolls out in the Purview compliance portal.
- August 2026: Protected PDF annotation for iOS and Android (current announcement).
The move also aligns with the broader “everywhere security” push within Microsoft 365. In 2025, the company extended sensitivity labels to Teams mobile chat and channels, and it has been gradually unifying the labeling experience across platforms. Adding annotation for protected PDFs in OneDrive closes one of the last major feature gaps in the mobile information-protection story.
How to Prepare Your Organization
Right now, there’s no download to install or switch to flip. The capability will simply appear as a server-side update alongside the August 2026 app refresh. But smart IT teams can start laying the groundwork.
For administrators:
- Audit label policies: Verify that sensitivity labels are applied to SharePoint and OneDrive files that contain PDFs. If your organization hasn’t yet deployed labels for PDFs, now is the time to pilot a small set. Use the built-in labeling reports in the Purview compliance portal to see which documents are protected and how often they’re accessed from mobile devices.
- Update user training: When the feature lands, walk your power users through the new annotation tools and remind them that protected documents remain protected—annotations don’t downgrade security. A short “What’s New” video or an intranet post can prevent a flood of help-desk tickets.
- Watch the Message center: Exclusive rollout dates and temporary service tweaks will appear in the Microsoft 365 admin center. Subscribe to alerts for “OneDrive” or “Purview” to stay informed.
- Consider pilot groups: If your tenant allows controlled feature rollouts, use Microsoft 365’s Targeted Release to test the annotation experience with a small set of users before broad deployment.
For end users:
- Keep your OneDrive app updated. Turn on automatic updates in your device settings so you get the annotation tools as soon as they’re live.
- Set realistic expectations. The annotation engine is built for quick markups—signing, highlighting, commenting—not for full document editing. For form fill or structural edits, you’ll still need a dedicated PDF application.
What Comes Next
August 2026 is a long 14 months away, and roadmap dates can slip. But the direction is unmistakable. After PDF annotation, expect Microsoft to close the loop for other file types—Word documents and Excel spreadsheets protected with sensitivity labels may eventually gain mobile editing, too. The company has already been testing real-time co-authoring on encrypted files in the desktop apps, and bringing that to mobile seems a logical next step.
There’s also the Copilot angle. Once you can annotate a protected PDF, you’ll likely want to ask the AI assistant to summarize a section or explain a clause—without breaking encryption. Microsoft has been working on “Copilot with protection,” a service that processes encrypted data in a secure enclave. Integrating Copilot into the OneDrive mobile PDF viewer could turn those annotated margins into a truly interactive knowledge layer.
For now, though, the mark of progress is small but significant: a highlighter tool that respects a digital seal. By August 2026, mobile work should feel a little less like a compromise.