Leaving the field label empty (no text = no label)
Using CSS style option in the field settings OR add a style to your theme. The easiest way is using the field settings if just hiding a few labels. HOW? Follow these steps:
Edit field with the label you want to suppress
Click [STYLES] tab on Element Settings window
Click [Add a style] button at bottom under CSS Styles
Choose Label-Text as selector (if you want to hide the label but not tooltip) or label (to hide label and tooltip)
Type display:none; in the CSS box
Save
The important thing to work out is whether you need or want the Required asterisk ‘*’ or Tooltip to still show in the absence of a label.
To keep the field required asterisk on show you will need to add further custom CSS override. As this markup is also hidden when you use either selector as described above. This is because the HTML markup for ‘Required’ is inside the label tag.