Line of Credit is a liability account in the books. So, you will need to create a new Line of Credit account in the Chart of Accounts.
If you're thinking of bank connect and download bank feed just like bank accounts or credit card accounts, you will need to create a new account this way:
Name: Line of Credit (LOC) Bank Name
Account Type: Credit Card
Detail Type: Credit Card
(Why Credit Card type? Because that's the only liability type account, you can connect in QBO banking tab).
If you don't need to connect then, you can create a new account this way:
Name: Line of Credit (LOC) Bank Name
Account Type: Other Current Liabilities
Detail Type: Other Current Liabilities
Once you have opened the new credit card type or other current liability type account, in your Banking tab where you see LOC deposit, click that transaction row, switch the radio button to RECORD TRANSFER (if it's in Add button) and select that account under Select Transfer Account. Select Record Transfer. Done. Next time when you have got a new deposit from the LOC, it should remember it.
Hope this helps!