Do you want to make sure candidates are not able to change their name and email address in Bullhorn when they apply for a new job?:
Go to myHaley > Job Boards > Settings > Applications.
Check the box next to "Disable changes to Name and Email Fields".
If you'd like to show a help tip to explain why these fields cannot be updated for applicants to see while applying, you can add it in Custom Tooltip. You may also want to explain the process for reaching out to your company to make a change to name/email if needed.
This will prevent the candidate from overwriting their name and email in Bullhorn.