Greetings, @erin-3localbroth.
Thanks for reaching out to the Community. I’m here to share some information about connecting a bank account to QuickBooks.
You can only have one banking information. You can add multiple bank accounts within QuickBooks, as well as credit card accounts as long as one login information.
In addition, here's an article you can read to learn more about the parent and subaccount setup of your chart of accounts: Create subaccounts in your chart of accounts in QuickBooks Online.
Lastly, I've got you this helpful article for ideas about how you can categorize your online banking transactions: Categorise and match online bank transactions in QuickBooks Online.
Keep me updated in the comments if you have any other questions. I'll be here to lend a helping hand.