To change the default phone or browser app on an Android device running on version 6.0 Marshmallow, select it from a list after accessing either function, and select the option to use the desired app always. Alternatively, modify the default apps for these functions from the Settings screen. Unlike older versions of Android OS, Marshmallow doesn’t require users to clear existing settings regarding default apps before setting new ones.
After installing a new browser or phone app, access either function by tapping on a Web link or initiating a phone call, tap the desired app to use as the default option, and tap Always. After setting the default app this way, the selection prompt shouldn’t appear when accessing the phone or browser function again. If you only want to use an app temporarily, tap the Just Once option.
To modify the default apps via the Settings screen, open the app drawer from the home screen, access the Settings app, and tap the Apps option in the Device section. Tap the cog icon in the upper-right corner, and tap the Default Apps option in the Advanced section. The Browser App and Phone App options should appear on the screen if you have multiple apps installed for these functions. Tap on the options, and tap on the icons for the desired default apps. After doing this, the selected apps should be listed under each function.