To switch which phone number is your assigned primary (default) number, click your name in the top right corner and select "Numbers"
Next, check out the crowns to the left of each number on your account.
A crown with a dark outline? [orange box above]
This is your current Primary number.
No crown? [green box above]
If there is no crown icon next to the number, that means it's not a number you own or it cannot be used as a primary number.
A crown with a faint outline? [blue box above]
This number can be your Primary number if you wish.
To change/switch your Primary number
Simply click the faint outline crown next to the number you want to be your new primary number. The page will refresh and you will see two things:
The crown outline is now dark.
This number has moved to the top of your list.
At the moment, the first number in the list is the primary number: 14159036786.
We want to make the third number the Primary number [green box above]. So, we click on that crown.
When the screen refreshes we notice:
A message confirming that the Primary number has been changed [red arrow].
The new Primary number is at the top of our list [green box].
The old Primary number is lower down in our list [red box].
You can change this primary number anytime using these same steps.
A number with this icon next to it means it is being used as a secondary number. Secondary numbers cannot be used for anything other than sending group messages. See this article HERE for more details.
To get help with removing a secondary number, click here.