Is there a sandbox where I can test if a process will work for me? If not, do you know how I can test a process without affecting my books?

Yes, there's a sandbox tool you can use to test, Kim.

Here's the link to the tools from our Intuit Developers:  Sandbox and testing tools

Another way to perform a test without affecting your books is by taking a test drive or using a 30-day trial of QuickBooks Online.

To provide clarification on how it works, here's an article that includes detailed instructions for recording a retainer: Record a retainer or deposit in QuickBooks Online.

Please leave us a response if you have other questions or need further assistance.