Microsoft has adopted the Chromium open source project in the development of Microsoft Edge on the desktop to create better web compatibility. This new Microsoft Edge runs on the same Chromium web engine as the Google Chrome browser, offering you best in class web compatibility and performance.
The new Chromium based Microsoft Edge is supported on all versions of Windows 7, Windows 8.1, Windows 10, Windows Server (2016 and above), Windows Server (2008 R2 to 2012 R2), and macOS.
Starting with Microsoft Edge Canary version 90.0.784.0 and Dev version 90.0.796.0, you can now turn on (default) or off to automatically show the quick menu when selecting text in PDF files opened in Microsoft Edge.
The quick menu shows the Copy, Search, Highlight, Add comment, and More actions (to see full menu) options instead of the full context menu you see when right clicking on selected text in PDF files opened in Microsoft Edge.
See also: Introducing quick menu for PDF text annotations | Microsoft Edge Insider Articles
This tutorial will show you how to enable or disable showing the quick menu when selecting text in PDF files opened in the Chromium based Microsoft Edge.
The PDF quick menu is part of controlled feature roll-outs, so not everyone will have this feature yet.
EXAMPLE: Mini menu when selecting text in PDF files opened in Microsoft Edge
Open Microsoft Edge.
Click/tap on the Settings and more (Alt+F) button (3 dots). (see screenshot below)
Click/tap on Appearance on the left side, and turn on (default) or off Show mini menu when selecting text in PDFs for what you want on the right side under the Context menus section.
If you do not see a left pane, then either click/tap on the 3 bars menu button towards the top left OR widen the horizontal borders of the Microsoft Edge window until you do.
You can now close the Settings tab if you like.