Microsoft Edge might likely be the default app for opening pdf files on your Windows 10 PC.
If you’ve installed Adobe reader app on your PC, you can set it as the default app for opening the pdf files.
All you need do is to set the pdf file association.
Right-click on any pdf file on the pc
Choose “Open With” and then click on “Choose another app”
Choose Adobe Reader from the list that shows up in the popup
Tick “always use this app to open .pdf files”