You can use the Map more link in the Mapping fields step of your sync. Product category is not a default field in Campaigns, so you will need to add a custom field for it.
You can do this from the Mapping fields page during Zoho Reports sync.
1. From the Navigation toolbar, select Contacts, then Sync Services.
2. Click Zoho Books and open an existing sync or create a new one.
3. Navigate to
Map Your Fields page and click
Map more.

4. Select the required field from the Zoho Books fields and check the New Field checkbox above Select Campaign Field dropdown.

5. A custom field is created and data is imported into that field.