Every package include group of subject that have special fee. You can create new subject and continue to assign the subject in the package.Here you'll learn how to assign subject in the package.
Click button icon assign
Choose existing list of subject that need to be assign on the package
Click button assign subject to confirm the subject
On the left, show the list of the subject and on the right to confirm if you do not include the subject on the package.
To delete subject, Workspace Owner will deleting subject on the list inside package.