What does the PDF & Web Label setting do?

There's a setting in the App Builder (specifically in the More area of the field settings) called “PDF & Web Label.” This setting allows a different field label to be shown on the Submission than the text displayed in the App. 

In the Advanced App Builder, you will find this setting under the More section of your Field Settings:

The value included in this field setting will display on the Submissions page on the website and on your Submission PDF, but not in the App.

For example, you could have a field in your App with a label that directs the user to input their name, but the PDF & Web Label could denote what type of data is being displayed in the Submission:

In this case, the user will see the field label 'Input Your Name Here' when completing a Submission in the App, but the resulting Submission will display the field label 'Employee Name' on the website and resulting PDF.