When you add a new Field, Field Section, or Field Group, you can choose whether you want them to show up in the Agent or Client Portals.

For example, in the Details Field Group, there is a section for any referral. If you want the whole Field Section to not appear in the agent and client portals, you can click on the star next to the Field Section so it's a clear star. That Field Section will not show up in those portals.

If you want to pick and choose which Fields agents and clients will see versus what they won't, you can click on the star to the right of the Field to change it to either a purple star or a clear one. If it's purple, the Field will show in the agent and client portals.

To continue with the above example, if there was a referral, you can choose to show who the client was referred by and possibly the company or agent that referred them. You probably don't want the client to see the referral amount or any other details about the referral so you could clear those stars and leave the referred by as purple.