You can set these permissions open the Add-ons menu from the Administration drop down and select the Configuration option under JExcel PRO in the sidebar.
Accessibility
JExcel enables administrators to restrict JExcel usage to specified user groups.
Start typing in the Display JExcel menu only for these user groups field and choose from the available groups.
If there is no group specified JExcel is available/accessible for every user.
Restricted functionality
In this configuration menu you can define what functions can be disabled in JExcel.
Show/Hide items
Here you can hide some action buttons from JExcel's user interface.