Editing Chart Axes
From LibreOffice Help
To edit the axes of a chart that you have inserted:
- Double-click on the chart.
A gray border appears around the chart and the menu bar now contains commands for editing the objects in the chart.
- Choose Format - Axis, then select the axis (or axes) that you would like to edit. A dialog appears.
- Select from the available sections and make the required changes (for example, select the Scale tab if you want to modify the scale of the axis).
- Click OK. In your document, click outside the chart to exit chart editing mode.