Loan from owner - Quickbooks desktop

Probably, deposit the money in a checking account and then create and use a liability account - for the loan balance - in the detail area of the deposit form.

This will increase cash and create a liability the company can pay back at a later time, according to the terms of the loan.

Create a new account, Long Term lIability, Account name:  Owner loan, tax mapping - B/S-Liabs/Eq.: Loans from stockholders.  You should be able to enter the opening balance on the account register