Yes, in desktop you can create as many companies as you want, creating a test company is good idea, then try out the things are not sure of in that test company before entering it in the real company books

Resolution for 'company before issue: 'Dear quickbooks!Can you add a test set without affecting the original set? thank you!' available: Yes.

The company before issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the company before issue yourself by looking for a resolution described in the article. If it is a complex company before issue or you are unable to solve the issue, you may contact us by clicking here or by using other company before support options.

For more information about resolving issues related to company before in Quickbooks/QBO or to get support for the issue 'Dear quickbooks!Can you add a test set without affecting the original set? thank you!', click the link below: