If you're unable to customize a report on the Platform, it could be due to the specific customization options available for that report. Most reports offer predefined filters and settings that allow for adjustments, but some may have limited customization features.
Ensure you've explored the available filters and column settings, typically found in the report settings or by clicking the gear icon within the most popular reports.
If your specific report is not customizable, please, explore other reports the Platform offers. And if the data you are interested in is provided by tracking device only and is not calculated by the Platform, consider using Custom Value Report.