Exporting Custom Columns to SharePoint

Hi Mario69 ,

If I understand you correctly, you should have first connected to Power BI Desktop using sharepoint as a data source, then created the Custom Column in Power Query, and now you want the Custom Column you created to exist inside the data source in sharepoint as well.
You can try these ways:

First, export the data with the custom columns from Power BI to an Excel file. You can do this by using the 'Export data' option from a visual that includes your custom columns. Once you have the Excel file, you can import this file into SharePoint. SharePoint has a feature that allows you to create a list from an Excel file.
Create a SharePoint list from Microsoft Excel

Or you can republish the converted data and report to Power BI Service and then embed the report in Sharepiont using the URL.
Embed a report web part in SharePoint Online - Power BI | Microsoft Learn

Or, you can try to use Power Automate to create a flow that takes the data from Power BI and creates or updates items in a SharePoint list. This method is more dynamic and can be automated to run on a schedule or triggered by specific events.
Get started with Power Automate - Power Automate | Microsoft Learn

Best Regards,
Dino Tao
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