How to set the default accounts on BlackBerry 10
To make sending emails and adding calendar appointments easy, you can set your default accounts on the device so you're instantly ready when adding new items. Instead of having to choose an email address or scroll through a list of calendars, you can set your default accounts on BlackBerry 10 for the ones you use most. This feature has been around on BlackBerry for a while and it comes in handy if you use some accounts more than others. Keep reading to see how to set the default accounts on BlackBerry 10.
Tap the Settings icon
Tap Set Defaults
Tap the dropdown menu and choose which account you'd like to set as default. You can do so individually for both email and the calendar.
Done and done! Now when you send and email or enter a new calendar event, these accounts will be selected by default (you can always change them within the respective app if you have more than one).