Cell Size is an environmental setting of the Flow Accumulation tool. It means you decide the cell size yourself when you run the tool. It says that "The default output resolution is determined by the coarsest of the input raster datasets" (Cell Size (Environment setting)—ArcGIS Pro | Documentation) so that should imply that the cell size is 10 m * 10 m = 100 square meters if you have not changed the default settings. You can always measure the size of your cells manually in your map if you want to be sure. (Just zoom in so you can se the individual cells).
Cell Size is an environmental setting of the Flow Accumulation tool. It means you decide the cell size yourself when you run the tool. It says that "The default output resolution is determined by the coarsest of the input raster datasets" (Cell Size (Environment setting)—ArcGIS Pro | Documentation) so that should imply that the cell size is 10 m * 10 m = 100 square meters if you have not changed the default settings. You can always measure the size of your cells manually in your map if you want to be sure. (Just zoom in so you can se the individual cells).
