You saw something on Facebook that grabbed your interest. You tapped on the link but you got directed to the page through the browser you didn’t want to use. You press your hardware camera button but it keeps opening your stock camera app instead of, let say Camera Zoom which you just bought. This happens because an app is already set as default to run a specific function.
There are numerous apps in the Play Store that can replace the functions that certain app is already assigned to do. To do so, you have to first “clear default” the default app and replace it with the app of your choice. This may sound difficult but it isn’t. This tutorial will guide you in changing the default apps on your Android smartphone device.
You may have seen the above picture. This will be shown whenever you execute a certain feature like clicking on a link, clicking on a sound file, clicking on a text file, etc. It can get quite annoying to tap “just once” button frequently, so you tap the “always” button. Doing this can get even more annoying if you haven’t found the perfect app and/or you just found your perfect app but you don’t know how to replace the previous app with this one. So how do you reset the default app?
Step 1:
Open your phone’s Setting app. If you don’t know where it is, just look for a “gear” 
like icon on your app drawer. The icon may look different depending upon the manufacturer or icon pack. Setting app can be opened by taping on the gear icon on the notification bar on most devices.
Step 2:
Tap on App Manager or Apps button. You can find it inside Settings. Just scroll one time and you’ll be able to see it.
Step 3:
Once you’ve found and opened App Manager or Apps, you’ll be greeted with a list of the apps you’ve downloaded, which is your default tab. Swiping left will enable you to see the apps on SD card, running apps and all apps. Slide over to “All” (because here all apps will be shown – both user installed and stock).
Step 4:
Let’s suppose you want to remove Firefox as your default browser and set Dolphin Browser as your new default. Tap on Firefox and you’ll see a screen like this.
Tap on Clear Defaults (scroll down if you don’t see it). Now whenever you click on a link, you’ll be prompted to select an application. Click on Dolphin Browser and tap on Always. This should make it the preferred default browser. 
Unfortunately, Android doesn’t let the user to look at all the default apps at once. There to avoid this, there is an app on the Play Store called Default App Manager and another app called Clear Defaults. Both these apps will let you look at a category such as Browsers, Phones, Cameras, etc. and remove or set a default app. You can remove the defaults one by one or all at once.
