Select Start > Settings > Apps > Default apps.

To change the default app, you can do either of the following:

1. Set a default for a file type or link type
   In the search bar, enter the file type or link type you want, then select it from the list of results. You can choose which app can open that file or link type.

2. Set defaults for applications 
   Select an app to see what file types or link types it can open. If you want to change something, select the file or link type, then choose your preferred app.