View the original community article here
Last tested: Apr 24, 2020
Let's say you have two or more measures, and want value_labels in your chart for only one but not the other?
Method1 (Pre-7.0): Input
transparent in the value label colors field. You'll also need to input another color for the other measure, or else both measure labels will be invisible.
Method2: Copy the blank character from this link and paste it into the 'Series' Value label
Transparent shown here working on 7.20.41