How best can I indicate conditionally required fields?

1. How do you highlight required fields?
2. What does indicate a required field mean?

How do you highlight required fields?

The "standard" that has evolved is that required fields have an asterisk (*) next to them. Sometimes the asterisk is red to help it stand out a bit.

What does indicate a required field mean?

When you make a field required, people must enter an answer to the field in order to submit their entry. When someone tries to submit an entry without filling out a required field, we highlight the problematic fields and display an error message to let them know the field is required.