Mandatory fields have to check in complaints/services over view screen

Hi i have a requirement please let me know how to find out mandatory fields for given fields?

1. Category1

2. Category2

3. Category3

4. Business Partner

5. Origin(Added By AET )

6. In parties involved Assignment block all the four partners are mandatory

    1)Employee Responsible

    2)Responsible Employee

    3)Responsible ORG Unit

    4)Sold_to_party

when i try to save the complaint in webui screen i need to do check EH_ONSAVE.

i want to know the data declaration part for given fields.

can we access from CRM_ORDER_READ?To data declarations