Make Acrobat or Reader the Default Owner of PDF Files on Windows 10
Associate PDF files to always open in Acrobat or Reader on Windows 10 - Mozilla Firefox
Step 1
 
1. Right-click the thumbnail of a PDF file, and then click Properties.
Step 2
 
2. In the file's Properties dialog box, click Change.
Step 3
 
3. Choose Adobe Acrobat Reader or Adobe Acrobat, and then click OK.
Step 4
 
4. In the Properties dialog box, click OK.
