In Dynamics 365 Sales, security roles control access to different forms, views, and records. To ensure that each department can only access their respective custom forms and views, you should assign security roles to the forms and views. This allows you to restrict users based on their department so they only see the forms and views relevant to them.

How it works:

Edit the form properties → Assign the form to specific security roles.

Edit the view properties → Restrict views based on security roles.

Ensure users have the correct security roles → Users in Department A will only see their assigned forms and views, and the same applies to Department B.