In many cases there are details which are important to survey or set as a parameter, or it is just needs to be displayed on the floorplan for better navigation or understanding. Labels are for this purpose, you can attach a label to any drawing part. You can draw lines with labels onto the floor plan like you would do it with pen and paper.
All labels are connecting to the nearest drawing elements at their starting point, therefore any drawing change updates the label appearence too. You can format the label text as you want, color, font size and font type can be adjusted to your needs.