In Adobe Captivate 8 for Mac, how do you set global settings? Such as no highlight on click etc.

You can set Global preferences by making changes  and related dialogues before you open a captivate file.

Select the File menu, and click Preferences to see the Global Preferences: General Settings dialogue:

You can also set your defaults, and adjust your recording settings.

Once you have a file open, these preferences settings are stored in that file as Project preferences.

Editing them with a file open will only affect that Project file, your Global setting will remain unchanged.