Hi Min Li,
The 8 parameters (as of August, a lot happens in Talent so I can't guarantee that it's correct today) is;
- Identification where you select the identification type for each identification number
- Compliance is where you can turn on the options to track disabilities or I-9 employment
- Number sequences is where you set up the shared number sequence code
- Position gives you the possibility to say if positions are assigned across the organization and if the position is required a department
- Personnel actions is an important feature where you say is actions are available or not for worker and positions (do you wish to track change is worker and positions)
- Performance is where you select the performance review rating model and say if it includes employee and manager rating and use weighted goals
- Advanced access contains a possibility to restrict access to worker information by legal entity
- Financial information is where you specify the dimensions available for a worker
As default the custom field isn't shared automatically, but as an administrator you can go to System Administration > Links > Personalization menu and choose if the field should be shared with some security roles or to all users (regardless of company).
Hope that helps!