If you only want to import last 7 days data into your model, @Vera_33 's solution will work. But this will not happen automatically. In Power BI Desktop, you need to click on Refresh button in Home ribbon to reimport the latest 7 days data. If you have published the report to Power BI Service, you should set a scheduled refresh for the dataset to refresh data every day. In this way, it will update the report to have latest 7 days data.
You can also use the User Interface to filter rows based on date type column. Filter by values in a column - Power Query | Microsoft Docs
If you want to load all data into the model but filter a date column on a visual (or on a report page, or on the whole report), you can use the relative date filter in filter pane or use relative date slicer. Use a relative date slicer or filter in Power BI - Power BI | Microsoft Docs This would update automatically every time you open the report.
Community Support Team _ Jing
If this post helps, please Accept it as Solution to help other members find it.