TL;DR:
Microsoft are embedding the Adobe Acrobat PDF engine into the Microsoft Edge built-in PDF reader. Rollout starting March or September 2023 depending on how your organisation manages your computer (scroll down for more detail).

Details:
Microsoft: “With the use of the Adobe Acrobat PDF engine, users will have a unique PDF experience that includes higher fidelity for more accurate colors and graphics, improved performance, strong security for PDF handling, and greater accessibility – including better text selection and read-aloud narration. There will be no loss of functionality with the use of the Adobe Acrobat PDF engine and these capabilities will continue to be free of cost. Organizations with Microsoft 365 E5 subscriptions can also view and validate certificate-based signatures and view PDF files protected through Microsoft Information Protection (MIP) at no extra cost.

Organizations with an existing Adobe Acrobat subscription can use the no-cost extension inside Microsoft Edge to unlock their subscription features—such as the ability to edit text and images, convert PDFs to other file formats, and combine files. Those who do not have an Adobe Acrobat subscription can purchase a license that enables access to these advanced features inside Microsoft Edge via an extension. There is no requirement to purchase an Adobe Acrobat subscription to use the Microsoft Edge built-in PDF free capabilities”.

Microsoft.

Availability:
Unmanaged (not managed with Intune) devices: March to September 2023.
Managed (with Intune) devices: March 2023 your organisation can choose to opt in. September 2023 earliest the rollout will begin, your organisation can choose to opt out. 31st March 2024 rollout out complete, no-one can opt out.

Source, related links, and references:
MC512918. 
Read about the Microsoft and Adobe partnership here.
Read about the Microsoft Edge and Adobe Acrobat PDF announcement here.
Read about the joint approach by Microsoft and Adobe engineering teams to secure the PDF experience here.

Page originally published:
11th February 2023 and kept up to date.