Reza Rad shares some tips on building mobile-friendly reports in Power BI:
Report fitted in my mobile screen, however when I see that in smart phone even with 5 inch screen, it is too small! texts are not readable in that size, and bar or column charts are too small to be selected with touch screen. When you design for smart phone size consider making sizes bigger. Also don’t use too many charts in one page, because it will make things small. few charts in each page will makes things readable and user will be able to highlight them and select items.
You can use formatting to make your font sizes bigger, and titles of charts bigger. However there are some charts and some elements that can’t be resized (for example labels inside tree map, or labels for x-axis in column chart below). Make sure to design big and clear with only few visualization elements in each page. Here is what I build and it shows in mobile phone nicely;
The upshot is that dashboards are about where we’d want mobile development to be—easy to use and “just works”—but reports have a ways to go yet.