Labels can be placed on the image using a special tool.

The type of labels is defined in View menu → Marks style. If you select field Numbering, a sequence number will be displayed next to each label. Labels can be displayed in the form of Arrows or V-like ticks.

To remove a label, place the cursor over it. When a cross appears on the right of the cursor, press the left mouse button and the label will be removed. Or you can remove all labels at once using the following command: View menu → Clear → Marks. МLabels can be moved while holding down the Shift key. When you switch to another tool from the toolbar, labels remain unchanged.