You can choose center, inside end, outside end, or best fit for the data label positions in the in the pane.

To quickly identify a data series in a chart, you can add data levels to the data points or the chart. By default, the data levels are linked to the values on the worksheet. You can see it in the format data labels pane.

Format Data Labels

Explanation:

Data labels can be formatted in Excel by selecting the set of data labels to format. To do this follow these steps.

Select Format tab in the Chart Tools tab. From Chart Elements button choose data labels to format. Click the Format Selection that appears below the drop-down menu.The other way is to right click the required set of data labels to format within the chart.To do this select  Format Data Labels. This command formats the data labels in Excel.This shows Format Data Labels pane at the right of the screen. This is where the data labels are formatted.In Label Options, set the positioning of data labels.This will be immediately applied to the chart.Close the Format Data Labels task pane after choosing the desired data label position.