Hi there, @aty.
Welcome to the Community. Let me share some clarification about importing the mortgage account in QuickBooks Online.
Currently, the bank feeds feature only supports bank and credit card accounts. The ability to convert it to Long Term Liability is unavailable.
The only way to handle mortgage in the system is by setting up the account manually in the Chart of Accounts. To create one, here's how:
- In QBO, go to the Accounting menu at the left pane to get to the Chart of Accounts.
- Tick the New button at the top right.
- In the Account Type drop-down, pick Long Term Liability.
- Enter the Detail Type and Name.

- Once done, hit Save and Close.
Also, you can try downloading transactions tied to the checking account from your bank's website. This way, you'll be able to upload the data directly to the Long Term Liability account.
Please follow these steps:
- Go to your bank's website and download the payments tied to the checking account.
- On the left navigation bar, click Banking.
- Press the drop-down arrow beside Update.
- Select Upload from file.

- Click Browse.
- Choose the file you want to upload.
- Hit Next.

- Under QuickBooks Account, select the Long Term Liability account, then press Next.

- Map the columns and click Next.
- Select the transactions to import and hit Next until finish.
For more information, as well as how to track what you owe and how to enter payments, I recommend the following article: Set up a loan in QuickBooks Online.
Please let me know if you need anything else. The Community and I will be here to help you.