Hi How can i access by sandbox UI from production UI using gear icon , i can not see any gear icon in my production app

Thanks for getting in touch with the Community, rahuldash-google.

You can find your Gear icon in the top-right corner of the screen in QuickBooks.

If you're referring to Intuit Developer, when you create a developer profile, you automatically receive a sandbox company. These are regionally-specific QuickBooks companies with sample data. They look and act just like the normal experience, and commonly come in handy to be used as a testing environment during development to see your code in action. You can also connect them to external testing tools, like Postman or Insomnia.

You'll want to be aware that sandbox companies are only to be used for app development. Intuit provides this environment, content, and sample data for non-commercial use and testing. If you need something for testing normal functions in QuickBooks, you can consider checking out our test drive accounts.

Here's how to create a sandbox company with Intuit Developer:
 

1. Sign in to your developer account.
2. Access the API Docs & Tools tab.
3. Choose QuickBooks Online Plus or QuickBooks Online Advanced.
4. If you picked QuickBooks Online Plus, specify a region from your Country drop-down list. This can't be changed later on.
5. Select Add.

You can create up to 10 sandbox companies. Each of them will be valid and active for 2 years.

I've also included a detailed resource about working with Intuit Developer which may come in handy moving forward: Create & test with a sandbox company

Please feel welcome to send a reply if there's any additional questions. Have a great Wednesday!