Modify X-axis, and Y-axis, show data labels, Titles, and Background in Power BI Column Chart
Open the Power BI tool and connect with the data source. I am taking Adventureworks for SQL Server as Connection.
1. Drag the Stacked Column Chart from the Visualizations window.

2. Took table of Sales.SalesOrderHeader table from AdventureWorks to create a column chart. The value is taken as subtotal and Axis is taken as DueDate. The following graph is generated.

Increase/decrease the font size of the X-axis and Y-axis:
In Visual go to the FORMAT button, which will show both X-axis and Y-axis

Expand the axis, then you will change the font and size of the font according to your need.

Format button help to change the background color, increase/decrease the size of the font.
Add data label in column Chart in Power BI
Select the chart and change the data label setting by going to the Format tab and selecting the data label as shown below:

The chart will show the data label on each bar:

Change Background in Power BI
Select the graph which needs to modify and then select the FORMAT tab and change the background of the graph.

Change TITLE in Power BI
Select the graph and choose the FORMAT tab and go to the title option.
