Although there are 2 or 3 ways to apply new category values for many records at one time, by far the simplest is to use the SET CATEGORIES option by selecting the Category Toolbar Button above the Contact List.
The Category Filter can be a useful tool for both searching and editing of categories.
Here's a scenario to consider the practical use of this feature. Suppose that I want to check 2 category values as being true for a group of records. I wish to change only those 2 values regardless of how many other categories might, or might not be checked within the records. I merely need to check the two categories that I wish to change and choose the option to SET CATEGORIES VALUES and click the Apply button
If there is only one name selected in the contact list at the time that you perform the above operation the Set Category Values option will apply your new values to ALL of the records displayed in the current view of the contact list. If you had more that one name selected then your new category values will be applied only to the selected records.
This help article applies to Intellect 3