Select either imperial (miles, feet) or metric (km, meters) for the units appearing in peak label distances and heights.
In addition to peak labels, you can display the peak height and/or distance from the camera position by checking the corresponding checkbox.
Selecting this setting brings up a screen where you can control the following:
With the 45 degrees setting, the labeling starts with the highest peak and ends with the lowest peak. If a label does not fit next to an existing label, it will be skipped. You can filter which peaks get labeled by filtering on a height or distance range, as described under Peak Filtering.