Microsoft released the Office Lens app for Windows 10 way back in 2014. It seems however that app is coming to the end of the road, with Microsoft announcing that the app is being deprecated.
On the support page for the app Microsoft writes:
Important: Certain cloud-based services in Office Lens for Windows, such as saving your pictures to OneDrive, OneNote, Word, PowerPoint, or PDF, will become unavailable after December 31, 2020. You can continue to use other features of the app as installed on your device. In addition, Office Lens for Windows 10 will no longer be available for download from the Microsoft Store as of January 1, 2021. To continue to enjoy all Office Lens features, we recommend downloading and using the latest version of Office Lens for iOS or Office Lens for Android on your mobile device.
It does not appear Microsoft plans to discontinue this useful app, though much of the functionality was built into the OneDrive app for iOS and Android.
It seems more likely that the app was a leftover from Windows Phone development, and no longer served a propose without a phone platform, much like many other UWP apps. It will remain available on iOS and Android.
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