Hi there, DuncansPools.

QuickBooks Desktop versions will let you set up a bank account without having to provide an account number. You will need to go to your Chart of Accounts and create it from there. Here's how:

1. Open your Chart of Accounts, then press CTRL + N.
2. Select bank, then click Continue.
3. Leave the Bank Acct. No. and Routing Number fields blank.
4. Click Save and close. 
5. Click No if you're prompted to set up Bank Feed.

Once set up, use that dummy account to mark your bills as paid. You can also check out the screenshots below.

Let me know if you need anything else.