Display validation errors in a workflow's required fields

The Display Validation Errors toggle, at the top right of the workflow builder screen

In the top right corner of your workflow builder screen, you'll find the Display Validation Errors toggle. By default, it's set to off, but it can be toggled on as desired.

This toggle will provide an error on required fields they aren't filled out, and add a message about the field being required beneath the field in red text. The text will be invisible until the user clicks on the field and then click out of it without entering a value.