A lending loan is a loan for which you are the lender and someone is paying you back on an amortized schedule. A lending loan is treated as an asset in Quicken that has a positive balance.
Add an Asset Account , where value of the asset is the amount you are lending.
In the final window of account setup, when you are asked Is there a Loan on this asset?, select No.
Open the account you just created, then click the Account Actions icon (the gear icon on the top of the register), and then choose Convert to a Lending Loan Account.
In the Convert this Asset to a lending loan dialog, click Convert,
Quicken creates an asset account with a payoff schedule. The account is identical to a "normal" loan account in Quicken. The only difference being the sign of the lending loan and its payments are opposite that of a "normal" loan.