How do you categorize a Business Loan Payment in Quickbooks?

You might want to post your question on the QuickBooks Community.

See https://quickbooks.intuit.com/learn-support/us-quickbooks-community/misc/03/community-us

You need to set up an account  for the loan in the chart of accounts for the outstanding amount of the loan then each payment from the checking account will be split between the principle amount paid on the loan and the interest paid.  In the QB forum you can ask for help in setting up your books correctly and/or seek out a local QB advisor for help.