A label component is piece of text that is displayed in the CRF. You can put this at the beginning of a questionnaire to give extra information, or show this as a condition after a certain answer to show what kind of effect it will have on the participation of the patient.
For components with the type label it is standard that the title is shown on the left on screen and next to it the text. That way you can choose to display a longer explanation than you do normally by filling them in in the field text instead of the title.
Finally, it is possible to hide the title, which causes only the text to be visible. This way you can use the extra space the field text offers without having to show an often unnecessary title.