I want to ask why I can't use $([OtherObject]RecId)? I got an error as such:
[OtherObject]cannot be used in this kind of expression because no such object exists.⁽¹⁾
Then on the change display field to "[Frs_CompositeContract_Contact]EmployeeCompany", I didn't have the field on my table as in the image below. Do I have to add the field in the Business Object?
Fatiha, the error message suggests the selected 'On Change' field is not a link field. Ensure you have selected the link field for 'Raise User'. You can also try using $([link:<LinkField>]RecId).
The presumption is that both 'Raise User' and 'Customer' are link fields to the same record, since you are populating with the other's RecId. There is the possibility that you are using a separate 'Company' business object, if this is the case please let us know the details of the link fields and we may be able to help further (I am doubtful as your form screenshot is for the Customer link field, but there is the possibility nonetheless).
If the Customer field already shows the Company Name then no changes should need to be made to the form, however, if this is not the case, you would need to select the field for the linked Business Object which shows this whether it is [Frs_CompositeContract_Contact]EmployeeCompany or otherwise (e.g. Company, CompanyDisplayName etc.).
can we set Customer field automatically populated with Adam's company and vice versa?
In order to automatically populate Customer on change of Company there would need to be a single point of contact for each Company i.e. a 1:1 relationship in some form.