Fields Parent

[tothewine]

How do I populate a field (1) of a linked record the parent field (2)

[dreginald]

You can do it with formula eg, assignedUserId=lead.assignedUserId;

[tothewine]

the field is "Prospect" not "Assigned user"

[dreginald]

I have mentioned Assigned User as an example and you may change to the field you are using. If the entity from where you need to map the field has a one to many relationship, this formula will work.
Else you have to map with https://docs.espocrm.com/administrat...linkmultipleid