While these two items are quite different, they can easily get mixed up. Here's a brief summary of the two:
Note: An external bank account can appear as both an account available for transfers, and as a linked account to view. 

External account transfer

• This is a transfer of funds between an account you own with us, and an account you own at another bank.
• External account transfer requires additional verification to be completed to allow transfers. See also, How do I add a new account for external account transfers?

Linked external accounts

• This is when you link accounts you have at other bank to your digital banking. These external accounts will display on your dashboard in a read-only form.
• Linked external accounts are view-only in digital banking. Transfers cannot be completed.