Kurt Buhler and Stepan Resl give you a card:
When a user arrives at your report, they should be able to answer their most important questions in a few seconds. To do this, we typically put the most critical information in the top-left of the report (where we often look first). This information should provide a high-level overview, whereas additional details should be placed at the bottom of the report, behind interactions, or on later pages.
An effective and popular way to call attention to important numbers in Power BI is by using cards and KPI core visuals.
Read on for several examples and a breakdown of how they work best.