We can set up a sandbox QuickBooks Online company by visiting our Intuit developer, Rahuldash. I can provide additional information and help you sign in to our Intuit Developer.

In QuickBooks Online, the sandbox company will generate transported data only. However, if you want the Sandbox company interface, you have

to sign in to their page.

We can start with the sandbox QuickBooks Online company connected to your Intuit Developer account. It gives you sample data for navigation purposes.

1. Sign in to your developer account.
2. Select the API Docs & Tools tab.
3. Select Add a sandbox company.
4. Select QuickBooks Online Plus or QuickBooks Online Advanced.
5. If you select QuickBooks Online Plus, select a country from the Country dropdown. Note: Sandbox companies are region-specific. 
6. Select Add.

You can create up to 10 sandbox companies. They are valid and active for two years.

We cannot open Sandboxes and QuickBooks Online firms in the same browser. Instead, you can:

• Use brands of browsers, one for your sandbox company and one for the QuickBooks Online company.
• Use private or incognito browsers.
• Switch between companies directly from the QuickBooks Online UI. In the open sandbox company or QuickBooks Online, select the Gear icon and then Switch Company.

Additionally, visit this Intuit Developer page for more ideas about sandbox companies. You can also join other developers on the Intuit Developer community forum.

Moreover, you can visit this article to learn more about Intuit Developer: Intuit Developer.

Let me know if you have questions about the QuickBooks sandbox company. Take care.