Thank you for posting query in Microsoft Q&A Platform.
Under copy activity, navigate to
mappingstab to control the schema of your sink. Instead of writing data to json. You can directly try writing data to csv as well.
Please note, make sure you import schema in your source dataset, which is fetching data from API. Under Copy activity mappings tab consider hitting import schemas. Once you see schemas there play with mappings between source and sink as per requirement.
Hope this helps. Please let me know how it goes and if any further queries.
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