Azure Cosmos DB has numerous preview features for which you can request access. Here are the methods for requesting access to these preview features.
- Navigate to the Preview Features section of your Azure subscription.
- Under Type, choose “Microsoft.DocumentDB”.
- Click on the feature you want to see in the list of available preview features.
- To participate in the preview, click the Register button located at the top of the page.
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Ref: Steps to register for a preview feature