Vikas Tiwari Thanks for posting your question in Microsoft Q&A. I assume you have defined APIs in API Management to get Cosmos DB data and would like to generate Power BI reports with that data. You can create a custom Power Platform connector to an API in API Management and then calls the API (managed by APIM) from Power Platform to get the data for generating reports. Check out doc: Export APIs from Azure API Management to the Power Platform for more info on this.
Note: Currently, Power BI is not supported in Q&A forums (the supported products are listed here) and please reach out to dedicated forum https://community.powerbi.com/t5/Get-Help-with-Power-BI/ct-p/PBI_GetHelp for any assistance such as accessing Power BI APIs, managing connectors or how to generate reports etc. in related to Azure Power BI. The product group for Power Apps can assist you with your questions.
If you have any questions in API Management, feel free to add a comment and would be happy to answer them. I hope this helps with your questions.
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