Set Firefox Focus as your default browser if you want it to open links by default. The instructions vary depending on your version of Android:

Android version 7 and above

1. Tap the menu button next to the address bar:

   

2. Tap Settings.
3. Under the General section, Tap the toggle next to Make Firefox Focus the default browser. This will open the Android Default apps menu to then set Firefox Focus as the default browser.

Android version 6

1. In the Settings menu on your device, tap Apps & notifications (it may be called Apps or Applications on some versions of Android).
2. Tap Advanced (you may have to tap on the Gear icon first on some versions of Android).
3. Tap Default apps.
4. Tap Browser app to open a list of choices.
5. Tap Firefox Focus to select it.

Android version 5 and older

Step 1: Clear the current browser that opens links

1. Open the Settings application and tap on Apps. (On some versions of Android this button is labelled Applications or Application manager and you may have to tap on Manage applications before the next step.)
2. Tap on the All tab.

   

3. Tap on the current browser that opens links. This is usually the default browser which is called "Browser" or "Internet".
4. Tap on Clear defaults to prevent this browser from opening links by default. If "Clear defaults" is greyed out, then either you have not installed another browser or you have installed another browser like Opera and it is set to be the default browser. If you have installed another browser, go back to the previous step and repeat with the default browser.

   

Step 2: Set Firefox Focus to be the default browser for opening links

1. Open a link in an Android application like the Mail application.
2. Tap on Firefox Focus and then tap on Always.