Please follow the steps below:
- Go to the admin page of your shopify store, for example: [https://dfo-api.myshopify.com/admin]
- Click on Apps
- Click on Manage private apps
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- Provide App details information
- On Admin API section expand Review disabled Admin API permissions section
- Grant read and write access to Orders, transactions and fulfillments operations
- Click on Save button
- Read the instructions and click on I understand, create the app
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