Auto Population of field value from one object's to the other object's field

Auto Population of field value from one object's to the other object's field

Hi. I have created a custom field called "Contact Email" in Potentials object. I need to auto populate this field value based on the "Contact Name" lookup value in the same object. The "Contact Email" in Potentials should get the value of the email of corresponding Contact Name from Contacts object. Is it possible using webhooks?