Steps to stop Microsoft Edge from opening PDF files by default:

• Open the Settings menu.-Go to Apps and select it. Select Default Apps from the drop-down menu. Select the option to choose a default app based on the file type. You may also change the default app for opening PDF documents by using the Set default by app option. Select the app you wish to make the new default for the.pdf file type by clicking the current default app.
• Using these procedures, set the PDF reader as the default via the context menu option: Open the File Explorer programme. Navigate to the folder containing a PDF document. Right-click the.pdf file and select 'Save As.' Select the Choose another app option from the Open with submenu. To open PDF files, choose the new default programme. Select the option to always use this programme to open.pdf files.

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